a) Solve x² + 4x - 8 = 0 by completing the square​

Answers

Answer 1

Answer:

x = 2 + 2i, x = 2 - 2i

Step-by-step explanation:

[tex] {x}^{2} - 4x + 8 = 0 \\ \\ {x}^{2} - 4x + 4 + 4= 0 \\ \\ {x}^{2} - 4x + {(2)}^{2} = - 4 \\ \\ {(x - 2)}^{2} = - 4 \\ \\ x - 2 = \pm \sqrt{ - 4} \\ \\ x - 2 = 2i \\ \\ x = 2 \pm 2i \\ \\ x = 2 + 2i, \: \: \: x = 2 - 2i[/tex]


Related Questions

Solve this simultaneous e
x + y = 26
3x + y = 56

Answers

Answer:

x= 15 and y= 11

Step-by-step explanation:

The goal here is to solve

x + y =26 and

3x + y =56 for the variables x and y.

First, let's work on your first equation, x + y =26

After this initial survey of the equations, the system of equations we'll set out to solve is:

x+y = 26 and 3x+y = 56

Let's start by solving x+y = 26 for the variable x.

Move the y to the right hand side by subtracting y from both sides, like this:

From the left hand side:

y - y = 0

The answer is x

From the right hand side:

The answer is 26-y

Now, the equation reads:

x = 26-y

To isolate the x, we have to divide both sides of the equation by the other variables

around the x on the left side of the equation.

and this is the final solution to your equation.

Next, let's solve 3x+y = 56 for the variable y.

Move the 3x to the right hand side by subtracting 3x from both sides, like this:

From the left hand side:

3x - 3x = 0

The answer is y

From the right hand side:

The answer is 56-3x

Now, the equation reads:

y = 56-3x

To isolate the y, we have to divide both sides of the equation by the other variables

around the y on the left side of the equation.

and this is the final solution to your equation.

Now, plug the earlier result, x=26-y, in for x everywhere it occurs in

y=56-3x.

This gives y=56-3(26-y). Now all we have to do is solve this for y,to have our first solution.

26-y evaluates to 26-y

Multiply 3 by 26-y

we multiply 3 by each term in 26-y term by term.

This is the distributive property of multiplication.

Multiply 3 and 26

1

3 × 26 = 78

Multiply 3 and -y

Multiply 1 and y

The y just gets copied along.

y

3 × -y = -3y

3*(26-y) evaluates to 78-3y

56 - 78 = -22

The answer is -22+3y

56-3*(26-y) evaluates to -22+3y

Move the 3y to the left hand side by subtracting 3y from both sides, like this:

From the left hand side:

y - 3y = -2y

The answer is -2y

From the right hand side:

3y - 3y = 0

The answer is -22

Now, the equation reads:

-2y = -22

To isolate the y, we have to divide both sides of the equation by the other variables

around the y on the left side of the equation.

The last step is to divide both sides of the equation by -2 like this:

To divide y by 1

The y just gets copied along in the numerator.

The answer is y

-2y ÷ -2 = y

-22 ÷ -2 = 11

The solution to your equation is:

y = 11

Lastly, to find the solution for x, we plug this answer for y into the earlier result that

x=26-y.

This gives x=26-(11). Now, simplify this.

26-(11) evaluates to 15

x= 15

So, the solutions to your equations are:

x= 15 and y= 11

Answer:

(15, 11 )

Step-by-step explanation:

Given the 2 equations

x + y = 26 → (1)

3x + y = 56 → (2)

Subtract (1) from (2) term by term to eliminate y, that is

2x = 30 ( divide both sides by 2 )

x = 15

Substitute x = 15 into either of the 2 equations and solve for y

Substituting into (1)

15 + y = 26 ( subtract 15 from both sides )

y = 11

solution is (15, 11 )

2x – 3y = -5
y = 2 + x
The value of y in the system of equations is:
y = -1.
y = -3.
y = 1.
y = 3

Answers

Answer:

y = 3

Step-by-step explanation:

2x-3y = -5 --------- (1)

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

substitute (2) into (1)

2x-3y = -5

2x-3( 2+x ) = -5

2x-6-x = -5

2x-x = -5+6

x = 1

substitute x = 1 into (2)

y = 2+x

y = 2+1

y = 3

4t + 2u
w;t= 2 and u= 1

Answers

15

Step-by-step explanation:

4t + 2u²- u³

4×2=8

2×1=2²=8

1³=1

8+8-1

16-1=15

I GIVE BRANLILSET

Maddie prepared 24 kilograms of dough after working 6 hours. How many hours did Maddie work if she prepared 40 kilograms of dough? Assume the relationship is directly proportional.

Answers

Answer:

10 hours

Step-by-step explanation:

24kg dough/6 hours = 4kg dough/hour

4kg dough / 1 hour

*10                *10        (multiply both sides by 10)

---------------------------

40kg dough/10hrs

A line includes the points (-8,8) and (6,4). Select the correct point slope form equations of this line. (Remember there can be more than one)



Group of answer choices

y-8=(-2/7)(x+8)

y+8=(-2/7)(x-8)

y-4=(-2/7)(x-6)

Answers

Answer:

y-8=(-2/7)(x+8) and y-4=(-2/7)(x-6)

Step-by-step explanation:

Point slope form equation: y - y₁ = m(x - x₁)

m is the same for all your answer choices, so you can disregard that part.

First point: (-8,8)

x₁ = -8; y₁ = 8

Plug those values into the point slope form equation and you get:

y-8=(-2/7)(x+8)

Do the same for the second point, and you get:

y-4=(-2/7)(x-6)

Answer:

first and third options

Step-by-step explanation:

The equation of a line in point- slope form is

y - b = m(x - a)

where m is the slope and (a, b) a point on the line

Calculate m using the slope- formula

m = [tex]\frac{y_{2}-y_{1} }{x_{2}-x_{1} }[/tex]

with (x₁, y₁ ) = (- 8, 8) and (x₂, y₂ ) = (6, 4)

m = [tex]\frac{4-8}{6+8}[/tex] = [tex]\frac{-4}{14}[/tex] = - [tex]\frac{2}{7}[/tex]

using (a, b ) = (- 8, 8 ), then

y - 8 = - [tex]\frac{2}{7}[/tex] (x - (- 8) ) , that is

y - 8 = - [tex]\frac{2}{7}[/tex](x + 8) ← first option

using (a, b ) = (6, 4 ), then

y - 4 = - [tex]\frac{2}{7}[/tex] (x - 6) ← third option

You have $125 in a savings account and you deposit an equal amount into your account each week. After 5 weeks the account holds $170. Write an equation that represents the amount y (in dollars) of money in the account after x weeks.

Answers

Answer: 10x=y

Step-by-step explanation:

So if you subtract 170-125 you get 50. If you divide 50 by the 5 weeks you geat 10. So there is ten dollars a week going into the bank account.

5/12<__<3/4 what answer goes in the blank

Answers

Answer:

We have:

5/12<__<3/4

To complete the blank, we need to find a number that is larger than 5/12, but smaller than 3/4.

This is ratter easy, the first step would be to write both limits with the same denominator.

we can rewrite the upper one as:

3/4 = (3/3)*(3/4) = 9/12

Where we multiplied the numerator and denominator by the same number, 3.

Now we have:

5/12 <  < 9/12

Then in the blank, we could input any number like:

5/12 + 1/12 = 6/12

6/12 is larger than 5/12, but smaller than 9/12

We also could use 7/12, or 8/12.

And those are the ones easy to find, actually, there are infinite numbers that can fill the blank.

Then to complete the answer we will write:

5/12 > 6/12 > 9/12

If the interest of sum of money is 6 yrs in 3/8 of the principal . what is the rate of interest?​

Answers

Answer :

R = 6.25%

Solution,

Let P is the principal. It means interest will be :

I=3/8 P

The formula for the interest is given by :

[tex]I=\dfrac{PRT}{100}\\\\\dfrac{3}{8}P=\dfrac{PR\times 6}{100}\\\\\dfrac{3}{8}=\dfrac{6R}{100}\\\\R=\dfrac{300}{8\times 6}\\\\=6.25\%[/tex]

Hence, the rate of interest is 6.25%.

How to I write 1 2/3 as an improper fraction help ASAP

Answers

You would write 5/3 for it to be an improper fraction
you would write it as five over three
[ 5/3 ]

Are the following equations parallel, perpendicular, or neither? y= 3x - 1 and y =
-1/3x + 10 *
Parallel
Perpendicular
Neither

Answers

Answer:

Perpendicular

Step-by-step explanation:

11. The table below shows the cost of comic books. Number of Comic Books Total Cost (dollars) 3 3.75 5 7 8.75 10 12.50 Based on the information in the table, which is the best prediction of the cost of 12 comic books?​

Answers

Answer:

$15

Step-by-step explanation:

The unit rate or how much a comic book costs = total cost ÷ number of comic books

Using any given pair, let's use the first row (3, 3.75):

Unit rate = [tex] \frac{3.75}{3} = 1.25 [/tex]

This means a comic book cost $1.25.

Therefore, 12 comic books would cost:

12 × 1.25 = $15

In a class of 12 boys and 8 girls, two students need to be chosen for classroom jobs.
What is the probability that Mary gets selected?

Answers

Answer:

55 percent chance or 11/20 or  0.55

Step-by-step explanation

If the store paid $75 for a clarinet and sold it for $100, did the store mark up the price by 30%?

Answers

Answer:

No

Step-by-step explanation:

30% of $75 is $22.50 (0.3×75=22.5)

$75+$22.50=$97.50, not $100

So, the store did not mark up the price by 30% because the original price ($75) plus 30% more does not equal $100.

Answer:

no

Step-by-step explanation:

What does the arrow represent?
Bouncing a Ball Height ha 0 Time

a. the ball is hitting the ground for the first time
b. the ball has hit the ground for the third time and is rising
c. the ball has reaches the maximum height of the first bounce
d. the ball has been thrown and is traveling towards the ground ​

Answers

Answer:

b number is the correct answer of the question

Answer:its a

a

Step-by-step explanation:

Answer this question correctly and I will give you brainlyist, 5.0 rating, and thanks. The question that you need to answer is in the screenshots below.

Answers

Answer:

so it should be D because after you check them all D is the only one that the watch would actually cost $50- sorry for the confusing ecplanation but im like 99.99999% sure its right

Step-by-step explanation:

Nick earns 3.5%
commission on every
car he sells. How much
would he earn if he sold
a $14.000 car?

Answers

The amount he would earn is $490.

What does multiplication mean?

Multiplication is the process of determining the product of a number. It is determined by following some mathematical processes. The sign used to represent multiplication is ×.

How much will he earn?

Commission = 3.5% x $14,000

0.035 x $14,000 = $490

To learn more about multiplication, please check: https://brainly.com/question/13814687

Factor using grouping: x³+ 3x² + 5x = 15

Answers

X= 1.288 or just 1.29 is the correct answer. When you factor, set each factor equal to zero.
1. Move all terms to one side of the equation, usually the left, using addition or subtraction.
2. Factor the equation completely.
3. Set each factor equal to zero, and solve.
4. List each solution from Step 3 as a solution to the original equation.

A decking company estimates how many gallons of stain each deck requires before starting construction. Apart from knowing the total area of each deck, which additional quantity will allow the decking company to make an accurate estimation

Answers

Answer:

Concept: Engineering Statistics

To make accurate estimations they need the total volume of the area.Hence they need the area coverage by the selected stain.Solution: Are covered by each gallon of stain This provides an accurate representation to a significant figure.

PLEASE HELP if you help you like to play among us
Subtracting a number is the same as adding its opposite.

Use this understanding to complete each of the equations below.
CLEAR CHECK

Answers

Answer:

-5 - (-7) = -5 + -7

= 2

-5 - 7 = -5 + -7

= -12

There are 32 desks in a room,
If x represents the number of rows of desks, which expression would equal the number of desks in each row?
32 x
32-x.
32 +x
32/x

Answers

Answer
32/x
Explanation
I think this is correct, the others wouldn’t make sense

The expression would equal the number of desks in each row is 32/x. Therefore, option D is the correct answer.

Given that, there are 32 desks in a room.

What is an expression?

An expression is a combination of terms that are combined by using mathematical operations such as subtraction, addition, multiplication, and division.

Now, x represents the number of rows of desks.

The number of desks in each row = Total number of desks in a room / The number of rows of desks

= 32/x

The expression would equal the number of desks in each row is 32/x. Therefore, option D is the correct answer.

To learn more about an expression visit:

https://brainly.com/question/13947055.

#SPJ5

The cost, including sales tax, of a Ford Focus SE is $19,392.70. If the sales tax is 6%, find the cost of the car before the tax was added.

Answers

Answer:

the price before taxes was $18,229.13

Step-by-step explanation:

what is m% of n please help

Answers

m% of n would technically be some amount of n. To find m%, you would have to do n * 0.m to find your answer

Please help i’m giving out brainliest || Q1

Answers

the answer would be a I'm my mind

it would be 8.5 ;
there is 8 box shaded and half of one box shaded
[ 0.5 = 1/2 ]

I need this done quick pls.

Answers

Answer:

58º

Step-by-step explanation:

The sum of a triangle's interior angles is 180º. We know two interior angles, and we can solve from there: 180-(65+57)=180-65-57=180-180-122=58.

What is the answer and plz give me step by step explaining

Answers

Answer: 5/7

Explanation:

You start with 6 + 8(x - 1) = 2(3x + 4)
Wow. That looks like a lot, so you need to take it one step at a time. Because of PEMDAS (Please Excuse My Dear Aunt Sally), which gives us the order of Parentheses (), Exponents(Baby Numbers), Multiply or Divide from left to right according to where it is in the problem, and Add or Subtract from left to right according to where it is in the problem, you need to look at your parentheses first. Let’s start with
8(x - 1). 8 is touching those parentheses all by itself, so it’s being multiplied with the stuff in the parentheses. 8 times x is 8x and 8 times 1 is 8. That gives you

6 + 8x - 8 = 2(3x + 4)

Do the same thing with 2(3x + 4). 2 is touching those parentheses all by itself so you multiply it by the stuff inside to get 6x + 8. You now have

6 + 8x - 8 = 6x + 8

But where do we go from here? Okay well what you’re trying to do is get a single x by itself on one side of the equals and the answer on the other side. So, we have

6 + 8x - 8 = 6x + 8

Let’s start on the left side with 6 + and - 8. If you have 6 and you take 8 away, you can’t because you’ll still need 2, so 6 - 8 = -2. That leaves you with

8x - 2 = 6x + 8

Then, you take the 6x from the right side and add it to the 8x on the left. You have 14x. This gives you

14x - 2 = 8

Look at -2. We want to get rid of that, so we would do the opposite of - which is + so we would add.

14x - 2 = 8
+ 2 + 2
——————
14x = 10

Now look at 14x, which is the same as 14 times x. The opposite of multiplying is dividing so divide.

14x = 10
/14 /14

X = 10/14 which simplifies into 5/7

Use the following function rule to find f(-7).
f(x) = 9x - 7
O 70
O-56
0 -70
56

Answers

The correct answer is -70 if you substitute in -7 for c the equation will be = -63 -7 = -70

Expand the following expression by using the distributive method. 6(3b-4c)

Answers

18b-24c. U take the six times the 3b and then the 6 times the -4c. U “distribute” the six with both values

James borrows $4,200 to pay his college tuition. He signs a 5-year simple interest loan. If the monthly payments are $78.40, what is the interest rate on the loan?

Answers

Answer:

2.4%

Step-by-step explanation:

Total amount of payments:

5 years * 12 months/year * $78.40/month =

= $4704.00

Amount of interest paid in 5 years:

$4704 - $4200 = $504

Amount of interest paid in 1 year:

$504/5 = $100.80

Annual percent rate of interest:

$100.80/$4200 * 100% = 2.4%

Answer: 2.4%

Which of the following slopes of a line passes through points (2, 3) and (4,7) ?
5
2
3
O

Answers

Answer:

2

Step-by-step explanation:

slope = (difference in y)/(difference in x)

slope = (7 - 3)/(4 - 2)

slope = 4/2 = 2

Answer: 2

Which graph best represents the equation y= 2/5x + 3

Answers

Answer:

I it is the one on the bottom.

Step-by-step explanation:

the graph on the very bottom
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