solve the equation
x2+4x-7=0
by completing the square
give your answers correct to 2 decimal places

Answers

Answer 1

Answer:

x ≈ - 5.32, x ≈ 1.32

Step-by-step explanation:

Given

x² + 4x - 7 = 0 ( add 7 to both sides )

x² + 4x = 7

To complete the square

add ( half the coefficient of the x- term )² to both sides

x² + 2(2)x + 4 = 7 + 4

(x + 2)² = 11 ( take the square root of both sides )

x + 2 = ± [tex]\sqrt{11}[/tex] ( subtract 2 from both sides )

x = - 2 ± [tex]\sqrt{11}[/tex]

Thus

x = - 2 - [tex]\sqrt{11}[/tex] ≈ - 5.32 ( to 2 dec. places )

x = - 2 + [tex]\sqrt{11}[/tex] ≈ 1.32 ( to 2 dec. places )


Related Questions

Exactly 1 1/3 yard of ribbon is needed to make a bow. Which of the following lengths of ribbon could be used to make a bow with the least amount remaining?

Answers

The answer choice which could be used to make a bow with the least amount remaining is; 1 2/5 yards.

Which Length of ribbon renders the least remainder?

It follows from the task content that the amount of ribbon remaining in each case can be evaluated as follows;

For 1 2/5 yards: 1 2/5 - 1 1/3 = 1/15. renders only 1/15 a yard to waste.

For 1 and 1/6 yards would render a waste of 1 1/6 yards since it is not possible to make a ribbon out of it.

1 2/10 yards would render a waste of 1 and 1/5 yards since it is not possible to make a ribbon out of it.

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What is the equation for ⨀C?

Answers

Answer:

A

Step-by-step explanation:

r^2 = (x - k)^2 + (y - h)^2

Answer: Choice A. (x-2)^2 + (y+2)^2 = 16

Work Shown:

(h,k) = (2,-2) is the center. So h = 2 and k = -2

r = 4 is the radius. We go 4 units from the center C to point P

Therefore,

(x-h)^2 + (y-k)^2 = r^2

(x-2)^2 + (y-(-2))^2 = 4^2

(x-2)^2 + (y+2)^2 = 16

E is in the corner by 10.5 on question 9

Answers

Answer:

see below

Step-by-step explanation:

7. The similar rectangles are W and Z.

8. EF = 18 * 1.8 = 32.4

9. BD = 20 / 2.5 = 8.

tell me weather 16641 is a perfect square by division method an please show me the solution too​

Answers

Answer:

yes

Step-by-step explanation:

you see we need to make pairs and then we divide each one by square numbers and I have given picture

Answer:

Yes, the number 16,641 is a perfect square.

Step-by-step explanation:

16641 is the 129th perfect square number

__________________________________________

1 2 9    

1 1 66 41    

1        

22  66      

44      

249  22 41    

22 41    

258   0    

 

Number = 16641

Square Root = 129

________________________________

Step-1 :

Make pair of digits of given number starting with digit at one's place. Put bar on each pair.

           

1 66 41    

Step-2 :

Now we have to multiply a number by itself such that the product ≤ 1

Here 1×1=1≤1, So divisor is 1 and quotient is 1. Now do the division and get the remainder.

 1        

1 1 66 41    

1        

0        

Step-3 :

Now , we have to bring down 66 and quotient 1 is multiplied by 2 becomes 2, which is starting digit of new divisor

 1        

1 1 66 41    

1        

2  66      

Step-4 :

2 should be the digit at one's place of new divisor because when 22 is multiplied by 2 we get 44.

So new divisor is 22 and next digit of quotient is 2. Now do the division and get the remainder.

 1 2      

1 1 66 41    

1        

22  66      

44      

22      

Step-5 :

Now , we have to bring down 41 and quotient 12 is multiplied by 2 becomes 24, which is starting digit of new divisor

 1 2      

1 1 66 41    

1        

22  66      

44      

24  22 41    

Step-6 :

9 should be the digit at one's place of new divisor because when 249 is multiplied by 9 we get 2241.

So new divisor is 249 and next digit of quotient is 9. Now do the division and get the remainder.

 1 2 9    

1 1 66 41    

1        

22  66      

44      

249  22 41    

22 41    

0    

Answer: 129 (proof 129^2) = 16,641 or 129 x 129 = 16,641

______________________________

Second Solution shortcut:

A perfect square is a number that can be expressed as the product of two equal integers.

The only way to accurately calculate if a number is a perfect square is to find the factors. Before we go through the trouble of finding the factors, there is a quick trick you can use to help determine if you need even need to do the extra work.

Try these steps first:

A number that is a perfect square never ends in 2, 3, 7 or 8. If your number ends in any of those numbers, you can stop here because your number is not a perfect square.

Obtain the digital root of the number. The digital root essentially is the sum of all of the digits. If you're lost, don't worry, we'll go over each step in more detail below.

All possible numbers that are a perfect square have a digital root of 1, 4, 7, 9.

Let's try it...

Step 1:

What is the last number of 16,641? It is this number: 16641. The answer is 1. Is 1 in the list of numbers that are never perfect squares (2, 3, 7 or 8)?

Answer: NO, 1 is not in the list of numbers that are never perfect squares. Let's continue to the next step.

Step 2:

We now need to obtain the digital root of the number. Here's how you do it:

Split the number up and add each digit together:

1 + 6 + 6 + 4 + 1 = 18

If the answer is more than one digit, you would add each digit of the answer together again:

1 + 8 = 9

What is the digital root of number 16,641?

Answer: 9

Step 3:

So now we know the digital root of 16,641 is 9. Is 9 in the list of digital roots that are always a square root (1, 4, 7 or 9)?

Answer: YES, 9 is in the list of digital roots that are always perfect squares. We can conclude that 16,641 could be a perfect square!

Factoring

OK, so now we know that 16,641 could be a perfect square. We have to find the factors of the number to be sure.

Here are all of the factors of 16,641:

1 x 16,6413 x 5,5479 x 1,84943 x 387129 x 129

Highlighted in orange above is the factor combination that makes 16,641 a perfect square. Do you see why? A number can only be a perfect square if the product of two exactly the same numbers is equal to the original number.

Here's the proof: 129 x 129 = 16,641

A) 15

B) 25

C) 40

D) 60

Answers

Answer:

may be 25

idk the real but might be 25

Step-by-step explanation:

someone do this thanks

Answers

Answer:

2

Step-by-step explanation:

12-2= m(2+3)

m= 10/5=2

Which table shows exponential decay?

Answers

Answer:

Table 1,

1 16

2 8

3 4

4 2

Step-by-step explanation

The equation for this function can be written as

y = 16^1/x

This is exponential decay.  

Answer: table 1

Step-by-step explanation:

How many cubes are needed to build the base of this structure?
A.6
B.3
C.5
D.4

Answers

Answer: C.5

The answer is 5.

Why is there a twenty character minimum on brainly? what a stupid idea

I agree with the other person. The answer is C 5 which can be shown in the diagram below.

The red outlines mark these blocks. Note that the upper two red blocks in the far right portion are underneath a set of blocks that are on the second story of this "building" of sorts.

Find the missing factor

Answers

Answer:

The missing factor is (9s+1)

Step-by-step explanation:

The missing factor is (9s+1) because of the following

(9s^2 + s) + (18s+2)

If we factor out s from 9s^2+s, we get s(9s+1).

If we factor out 2 from 18s+2, we get 2(9s+1)

putting these together, we get s(9s+1) + 2(9s+1). Factoring out the common term of 9s+1, we get (9s+1)(s+2). therefore, the missing factor is 9s+1

What is the measure of < B, in degrees?

Answers

Answer:

B. 32°

Step-by-step explanation:

Since two of the sides are 10 in length, then we can infer that ∠A and ∠C are congruent. So, both equal 74°. You add 74 + 74 + x = 180, x would equal 32°.

Answer:

B

Step-by-step explanation:

sum of angle in triangle is 180

and since its isosceles triangle, it means <C will be same with <A

so we know that A + C = 148.

so the value of B will be like this

B = 180° - (A+C)° = 180 - 148 = 32°

Don and Dan went fishing. Don caught 6 times more mass of fish than his brother. Together they caught 4.2 kg of fish. What mass of fish did each of them catch? Please help! :))

Answers

Answer:

Don caught 3.6 kg and Dan caught 0.6 kg.

Step-by-step explanation:

Set up a system of equations:

Don's fish is the variable a and Dan's fish is the variable b.

a + b = 4.2 (1)

a=6b          (2)

We can substitute a in the first equation using the second equation, so:

6b + b = 4.2

7b = 4.2

b = 0.6 kg

Dan caught 0.6 kg. Then, we can use equation 2 to find how much Don caught.

a = 6 x 0.6

a = 3.6

Don caught 3.6 kg.

Explain why the initial value of any function in the form of F(x)=a(b^x) is equal to a

Answers

Answer:

When comes to initial value, x is equals to 0.

So x = 0 is substitute into the function.

In Indices Law, any values to the power of 0 will be 1.

So the initial value of function will be :

[tex]f(x) = a( {b}^{x} )[/tex]

[tex]f(0) = a \times {b}^{0} [/tex]

[tex]f(0) = a \times 1[/tex]

[tex]f(0) = a[/tex]

PLEASE HELP - PLEASE SHOW WORK Given the following functions, find each of the values: f(x)=x^2−7x+6 g(x)=x−1 (f+g)(−5)= ______ (f−g)(4)= ______

Answers

Answer:

(f+g)(-5) = 60(f-g)(4) = -9

Step-by-step explanation:

These are the values we will need:

  f(-5) = (-5)^2 -7(-5) +6 = 25 +35 +6 = 66

  f(4) = 4^2 -7(4) +6 = 16 -28 +6 = -6

  g(-5) = -5 -1 = -6

  g(4) = 4 -1 = 3

__

(f+g)(-5) = f(-5) +g(-5) = 66 +(-6)

(f+g)(-5) = 60

__

(f-g)(4) = f(4) -g(4) = -6 -3

(f-g)(4) = -9

which is the right answer because i am in the middle of two and can not dicide which to chose

Answers

Answer:

XZ

Step-by-step explanation:

Line segments are straight lines, not curves.

The only line is XZ, the rest are arcs

Answer:

Step-by-step explanation:

I believe that it’s yz

Points A and B lie on a circle with center O such that
the length of minor arc AB is 1/3 the circumference of
the circle. What is the degree measure of central angle
АОВ ?
A. 45
B. 60
C. 90
D. 120

Answers

Answer:

D. 120

Step-by-step explanation:

1/3*360= 120

Option D

a card is drawn at random from a pack of 52 playing cards. find the probability tht the card drawn is neither an ace nor a king

Answers

Answer:

[tex]\frac{11}{13}[/tex]

Step-by-step explanation:

There are 4 aces and 4 kings.

[tex]\frac{8}{52} =\frac{2}{13}[/tex]

Now just subtract that from 1.

[tex]\frac{11}{13}[/tex]

g(x) = 4x + 1

What is g(3)?

Answers

Answer:

D.13

Step-by-step explanation:

g(3) = 4(3) + 1 = 12 + 1 = 13

Answer:

D. 13

Step-by-step explanation:

g(x) = 4x + 1

g(3) = 4(3) + 1

replace x with 3

g(3) = 12 + 1

g(3) = 3

This is the answer

200 + 500 - 30 =
solve​

Answers

Answer:670

Step-by-step explanation:

200 + 500 - 30 =

700-30

670

200 + 500 =700 -30 = 670

The science club is experiencing a growth in membership. On average, they are
seeing 2 new members sign up each week. If they started with 10 members which
function, S(x), represents the number of members in the science club after x weeks?

Answers

Answer:

S(x)= 10+2^x

Step-by-step explanation:

The correct function which represents the number of members in the science club after x weeks is,

S (x) = 10 + 2ˣ

We have,

The science club is experiencing a growth in membership.

On average, they are seeing 2 new members sign up each week.

Here, they started with 10 members.

Hence, The function S (x) which represents the number of members in the science club after x weeks is,

S (x) = 10 + 2ˣ

Where, x is number of weeks.

Therefore, The function is,

S (x) = 10 + 2ˣ

Learn more about the function visit:

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The range of which function is (2,00)?

Answers

Answer:

the range of the function is ∞

If you wanted to build a raised garden bed that was 4ft by 4 by 1
How many bags of dirt do you need to fill it right up to the top.The dirt comes in 0.75 cubic feet per bag

Answers

Answer:

22 bagssss i am right because i did 4 time 4 times 1 and got 16 and then i divided that by 0.75 and got 21.33333 and since you can't get a 0.3333333 of a bag you have to get one extra so it would be 22

Step-by-step explanation:

please help!!!!!!!!!!!!!

Answers

Answer:

C

Step-by-step explanation:

C is the correct answer because the other 3 points are not correct when you put the numbers into the equation.

y = 16 + 0.5x

20 = 16 + 0.5(8)

20 = 20

the answer is indeed c!!!

1)If the coefficient of anyone of the variables is zero, what will be the nature if the equation? 2)What is a solution of a system of equations?

Answers

Answer:

1) If the coefficent of any variable is zero then the answer of the variable is 0.

2) There are two answers in a system of equations.

A class has 18 students. The teacher asks how many students in the class have pets and finds 5/9 of the students have pets. How many students have pets? * 1 point 9 8 10 11

Answers

Answer:

9 students

Step-by-step explanation:

5/9 of 18 is 10

A shop has a sale that offers 20% off all prices. On the final day they reduce all the sale prices by 25%. Linz buys a radio on the final day. Work out the overall percentage reduction on the price of the radio.

Answers

Answer:

40%

Step-by-step explanation:

You can plug in 100 as the price of the radio to see how much the price decreased.

20% off of 100 will make it $80.

Then, with the 25% discount, it will be worth $60.

So, $40 was taken off, and 40÷ 100 is 0.4, so the overall percentage reduction was 40%

Answer: 40% reduction

•To answer this, we have to find the price of each percentage.

•This can be found by subtracting the percentage from 100.

Sale price- 100 - 20 = 85
Last day Price- 100 - 25 = 75

•Now multiply these two values together after dividing both numbers by 100 first.

80/100 = 0.8
75/100 = 0.75

0.8 * 0.75 = 0.6

•Then multiply by 100 to find the percentage

0.6 * 100 = 60

•60% is the end price.
But to find the overall reduction, subtract 60 from 100...

100 - 60 = 40

Leaving us with the answer..
40% reduction on the price.



A number is selected from the set (1, 2, 3, 5, 15, 21, 29, 38, 500). If equal elemental probabilities are assigned, what is
the probability that the number chosen is either less than 29 or odd?

Answers

Answer:

[tex]\frac{7}{9}[/tex] OR 77.78%

Step-by-step explanation:

So, we first need to find out how many numbers fit the "less than 29 or odd" group.

This would be: 1, 2, 3, 5, 15, 21, and 29, which is a total of 7 numbers.

Next, we figure out the total amount of numbers in the population.

This would be: 1, 2, 3, 5, 15, 21, 29, 38, and 500, which is a total of 9 numbers.

Finally, we put the first number (7) over the total (9) = [tex]\frac{7}{9}[/tex]

[tex]\frac{7}{9}[/tex] is now able to be written in a percentage, if you need.

The probability is [tex]\frac{7}{9}[/tex] OR 77.78%


In the barn, there are horses and chickens. There are 11 heads and 32 legs altogether. How many chickens are there?

A. 6
B. 5
C. 4
D. 3

Answers

Answer:

6 Chickens

Step-by-step explanation:

Let  H represent the number of horses and  C represent the number of chickens. Since there are 32 legs altogether this means that on equation to use would be given by:

2C  +  4 H  =  32     (Eq. 1)

Another equation can be made from the fact that there are 11 heads or 11 animals altogether which can be written as:

C  +  H  =  11    (Eq. 2)

From Eq. 2, solve for the number of chickens:

C  +  H  =  11

C   =  11  - H    (Eq. 3)

Substituting Eq. 3 in Eq. 1, the number of horses can be determined:

2 C  +  4 H  =  32

2 ( 11  −  H )  +  4 H  =  32

22   −  2 H  +  4 H  =  32

2H  =  32  − 22

2 H  = 10

H = 5               Eq.4

Putting Eq.4 in Eq.1

2C + 4*5 =  32

2C = 32 - 20

2C = 12

C = 12/2

C = 6

find the missing coefficient. (5d-7)(5d-6)=25d^2+__d+42

Answers

Answer:

[tex]-65[/tex]

Step-by-step explanation:

[tex](5d-7)(5d-6)[/tex]

[tex]5d(5d)+5d(-6)-7(5d)-7(-6)[/tex]

[tex]25d^2+-30d+-35d+42[/tex]

[tex]25d^2+-65d+42[/tex]

The missing coefficient of [tex]d[/tex] is [tex]-65[/tex].

Answer:

25d^2 -65d +42

Step-by-step explanation:

(5d-7)(5d-6)=25d^2+__d+42

FOIL

(5d-7)(5d-6)=

First  5d*5d = 25d^2

Outer  5d*-6 = -30d

Inner  -7*5d = -35d

Last = -7*-6 = 42

Add them together

25d^2 -30d -35d +42

25d^2 -65d +42

a family of 8 has 3 of them being males what proportion of the family is female​

Answers

Answer: not very sure but i think that may be 5

Step-by-step explanation:

I think it is 5 idk I could be wrong

HELP ME PLEASE WHAT IS THE ANSWER OF THE FRACTIONS

Answers

-2 1/5

at least I think so lol

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