Brainliest and 15 points

The work of a student to solve a set of equations is shown below:

Equation 1: x + 2y = 10
Equation 2: 2x + 5y = 15

Step 1: −2(x + 2y) = −2(10)
2x + 5y = 15

Step 2: −2x − 4y = −10
2x + 5y = 15

Step 3: 1y = 5

Step 4: x + 2(1) = 10

Step 5: x = 8


In which step did the student first make an error?

Step 1
Step 2
Step 3
Step 4

Answers

Answer 1

Answer:

Step 2 has error and step 4 has error.

Step-by-step explanation:

Here we can see that elimination method is  applied to solve the  system  of equations  for which -2 is multiplied both sides of equation first

-2(x+2y)=-2(10 which is correct

but in step 2

left side is -2x-4y and the right side is -10 which has to be -20 which makes this step wrong and this is the error made by student.

in Step 4 also ,value of the y has to be 5 but student plugged y =1 which is also error by student.

Correct solution is

   -2x-4y= -20

     2x+ 5y= 15

on adding ,we get

y = -5

plugging y =5 in equation x+2y= 10 ,we get x+2(-5) =10 ,we get x = 20

therefore (20,-5) is the  solution

Answer 2

Answer:

step 2

Step-by-step explanation:


Related Questions

Find the measure of the indicated angles below.Drag the points to show the measure of the four angles

Answer Plzz​

Answers

Answer

A. Angle E = 113°

B. x = 16°

Explain

Number A

92 + 70 + 85 + ? = 360

162 + 85 + ? = 360

247 + ? = 360

? = 360 - 247

? = 113°

Number B

108 + 84 + ( x + 30 ) + ( 2x + 18 ) = 360

(180 + 84 + 30 + 18) + (x + 2x) = 360

312 + 3x = 360

3x = 360 - 312

3x = 48

x = 48/3

x = 16°

#LearnWithBrainly

What is the area of the irregular figure?

Answers

Answer:

106 m

Step-by-step explanation:

Brₐinliest plz close to leveling up

Answer:

Pretty sure it 13440

Sorry if its wrong but hope this helps.

Abigail is 54. Inches tall which of the following is Abigail height

Answers

Answer:

4.5 feet

Step-by-step explanation:

One foot is 12 inches, therefore she is 4 (12x4=48) and she would have 6 left over which is half of a foot. (:

A shopper bought 7 ears of corn and 6 pounds of bananas and paid $5.15. At the same store, another shopper bought 4 ears of corn and 1 pound of bananas and paid $1.85 . What is the price of an ear of corn?


Please help!

Answers

Answer:

$0.70 per ear of corn

Step-by-step explanation:

Let c = Ear of corn

Let b = pound of bananas

First shopper:

7c + 6b = $5.15

Second Shopper:

4c + 1b = $1.85

Solve one equation for b since you are solving for c:

4c + 1b = $1.85

b = $1.85 - 4c

Substitute into other equation:

7c + 6b = $5.15    <---  b = $1.85 - 4c

7c + 6 ($1.85 - 4c) = $5.15

7c + $11.1 - 24c = $5.15

-17c + $11.1 - $11.1 = $5.15 - $11.1

-17c /-17 = -$11.85 /-17

c = $0.70 per ear of corn

Leave a like and mark brainliest if this helped

5. Find the next 4 terms of the sequence
47, 45, 40, 32, 21, , , , ,

Answers

Answer:

7      -10     -30     -53

Step-by-step explanation:

47-2 = 45

45-5 = 40    (2+3=5)

40-8 = 32   (5+3=8)

32-11 = 21(8+3=11).........

21-14 = 7

7-17 = -10

-10 -20 = -30

-30-23 = -53

When I have walked 20% of the way to school, I have 1200 metres more to walk than when I have 20% of the walk remaining.

How far, in metres, is it from my home to my school?

Answers

Answer:

The house is 2000 meters from the school.

Step-by-step explanation:

Given that, when I have walked 20% of the way to school, I have 1200 meters more to walk than when I have 20% of the walk remaining, to determine how far, in meters, is it from my home to my school the following calculation has to be done:

100 - 20 = 80

80 = 20 + 1200

80 - 20 = 1200

60 = 1200

1200/60 = 20

20 x 100 = 2000

Therefore, the house is 2000 meters from the school.

Surface Area:Question 10

Lamar plans to paint the net above before folding it into a

triangular prism. What is the surface area he will paint?

13 cm

10 cm

Select one:

12 am

13 cm

840cm

20 cm

O

780cm

810cm

ОО

0 720cm

Answers

Answer:

Don't understand 12am like how

Given that the discriminant of a quadratic equation is 1, determine the number of real solutions.

Answers

Any positive discriminate has a quadratic with 2 real solutions

The data modeled by the box plots represent the battery life of two different brands of batteries that Mary tested. (a) What is the median value of each data set? (b) Compare the median values of the data sets. What does this comparison tell you in terms of the situation the data represent? For 100 point pls​

Answers

Answer:

a brand x = 13 (median ) brand y = 16 median

Answer:

A) Median value is depicted on a box plot by the vertical line that divides the rectangular box. Therefore: Median value for Brand X = 13 and Median value for Brand Y = 16. B) Brand Y has a higher median value (16) than Brand X (13). This implies that brand Y has a battery life that last longer than brand X.

Suppose that out of 30 gift cards in a

prize box, there are 7 for restaurants,

What is the probability that a restaurant

gift card will be drawn?

Answers

Answer:

7/30

Step-by-step explanation:

Henry was thinking of a number. Henry divides by 2, then adds 10 to get an answer of 15. What was the original number?

Answers

10 bc 10 divided by 2 is 5 then 5 plus 10 = 15

Answer:

Henry was thinking of the number 10.

Step-by-step explanation:

Variable x = Henry's original number

Set up an equation:

x ÷ 2 + 10 = 15

Isolate variable x:

x ÷ 2 = 5

x = 10

WILL MARK BRAINLIEST!!
In a survey conducted at a pet store, 150 customers were asked if they owned
birds or fish. The survey data are shown in the relative frequency table.
Own a bird
Do not own a
bird
Total
Own fish
0.04
0.08
0.02
0.86
Do not own fish
Total
What percentage of the people surveyed own a bird?

Answers

Using proportions, it is found that the percentage of the people surveyed own a bird is given by:

C. 6%.

What is a proportion?

A proportion is a fraction of a total amount, and the measures are related using a rule of three. When the proportion is multiplied by 100%, a percentage is found.

The proportion of people who own a bird is:

p = 0.04 + 0.02 = 0.06.

Hence the percentage is of 6%, which means that option C is correct.

More can be learned about proportions at https://brainly.com/question/24372153

#SPJ1

HELPPPPP ME PLEASEE

Answers

Answer: <

6.12 x 10^4 < 612,000

Step-by-step explanation:

Answer:

<

Step-by-step explanation:

because 6.12 × 10^4 = 61,200 and 612,000 is obviously a way bigger number, so greater than symbol is the correct answer.

How do you Find the value of x.

Answers

Answer: 65

Step-by-step explanation: well 115 is 115 on the opposite direction therfore 65 would be 65 on the opposite side also please give brainlest i am only one away from leveling up

a1 + a2 + a3 + a4 + a5

Answers

a15 i tbinkkjshajhshbs

Expressions with Irrational Numbers: Mastery Test 1 Type the correct answer in the box. The product of 2/3 and 3v12 in simplified form is Reset

Answers

Answer:

[tex]$\frac{1}{6}$[/tex]

Step-by-step explanation:

Expressing the irrational numbers into its simplified form :

Given :

The product of  [tex]$\frac{2}{3}$[/tex]  and  [tex]$\frac{3}{12}$[/tex]

Therefore,  

[tex]$=\frac{2}{3} \times \frac{3}{12}$[/tex]

[tex]$=\frac{2}{12}$[/tex]

[tex]$=\frac{1}{6}$[/tex]

So the simplified form is [tex]$\frac{1}{6}$[/tex]

At a recent meeting, the manager of a national call center for a major Internet bank made the statement that the average past-due amount for customers who have been called previously about their bills is now no larger than $20. Other bank managers at the meeting suggested that this statement may be in error and it needs to be tested. The file called Bank Call Center attached below, contains data for a random sample of 67 customers from the call center population. What should be conducted based on the sample data? Test using α = 0.10

Answers

Answer:

As the calculated z does not fall in the critical region we fail to reject H0 and conclude that there is sufficient evidence that the average past-due amount for customers who have been called previously about their bills is now no larger than $23.

Step-by-step explanation:

As the standard deviation for the past due amounts is 63

The sample size n= 67

1) Formulate the null and alternate hypothesis

H0: u ≤ 23 against the claim Ha: u > 23

2)  The test statistics is

Z= x- u / σ/ √n

z= 20- 23/ 63/ √67

z= 0.00581

z= 0.006

3) The significance level ∝= 0.1

4) The critical value for ∝= 0.1 is Z > ±2.33

5) As the calculated z does not fall in the critical region we fail to reject H0 and conclude that there is sufficient evidence that the average past-due amount for customers who have been called previously about their bills is now no larger than $23.

help? is this right or no?

Answers

Answer:

C

Step-by-step explanation:

Symmetry means to have the same structure on both sides. So, imagine a mirror reflecting, lets say half a piece of bread the structure will be the same on both sides.

pls give brainlist if helpful

A function is defined by the rule f(x) = 11 - 2x. What is the value of f(-3) ?

Answers

Answer:

17

Step-by-step explanation:

11 - 2(-3) = 11 + 6 = 17

should put -3 where x is

NO LINKS!!!!!!!!! please solve it and explain it.

Answers

Answer:

Linear: y = 2x-1

Step-by-step explanation:

slope 1 = (5 - -9)/(3 - -4) = 14/7 = 2

slope 2 = (19-5)/(10-3) = 14/7 = 2

equation: y = mx + b          b = y-mx = 19 - 2*10 = -1

y = 2x - 1

Penny is going to fly her plane to her sister's house, which is 544.32 miles away. Penny's airplane flies at an average speed of 672 miles per hour. How long does it take Penny to fly to her sister's house?

Answers

Answer:

0.81 hour

Step-by-step explanation:

Given data

Distance=  544.32 miles

Speed=  672 miles per hour.

We know that

Speed= distance/time

Substitute

672=  544.32/time

cross multiply

time*672= 544.32

time= 544.32/672

time= 0.81 hour

HELP WILL MARK BRAINLIEST

Answers

Answer:

Volume = 12

Step-by-step explanation:

Answer:

12cm³

Step-by-step explanation:

L=3cm

W=2cm

H=2cm

Volume=L*W*H

Volume =3*2*2

=12 cm³

TAKE HOME
1. Find the angle between the vectors:
i-23 + 5k and 3i+j - 2k

Answers

Answer:

The angle between the two vectors

∝ = 64°

Step-by-step explanation:

Step(i):-

Given that the vectors

                           [tex]a^{-} = i^{-} - 2j^{-} +5k^{-}[/tex]

          and

                         [tex]b^{-} = 3i^{-} +j^{-} -2k^{-}[/tex]

[tex](a^{-} . b^{-} ) = (i^{-} - 2j^{-} +5k^{-} ) . (3 i^{-} + j^{-} - 2k^{-} )[/tex]

           =  3 (i⁻ . i⁻) - 2(j⁻.j⁻) -10(k⁻.k⁻)

          = 3 - 2 -10

          = -9

Step(ii):-

Let '∝' be the angle between the two vectors

                    [tex]cos\alpha = \frac{a^{-}.b^{-} }{|a||b|}[/tex]

                  [tex]cos\alpha = \frac{|-9| }{\sqrt{1+4+25}\sqrt{9+1+4} }[/tex]

                 [tex]cos\alpha = \frac{|-9| }{\sqrt{30}\sqrt{14} }[/tex]

               [tex]\alpha =cos^{-1} ( \frac{|-9| }{\sqrt{30}\sqrt{14} })[/tex]

              ∝ = cos⁻¹(0.4392) = 63.947

Final answer:-

The angle between the two vectors

               ∝ = cos⁻¹(0.4392) = 63.947

                ∝ = 64°

Can someone pls helpppp ASAP this is due in 25 min :(

For the right triangles below, find the values of the side lengths d and a.
Round your answers to the nearest tenth.

Answers

Answer:

a = 1.4 and d = 6.9

Step-by-step explanation:

To get the value of d and a, we will use the SOH CAH TOA identity

For the first tringle;

Opposite = d ((opposite angle 60 degrees)

Adjacent = 4

Tan theta = opp/adj

Tan 60 = d/4

d  = 4tan60

d = 4(1.732)

d = 6.9

For the second triangle;

Opposite = a

Hypotenuse = 2

Since sin theta = opp/hyp

Sin45 = a/2

a = 2sin45

a = 2(0.7071)

a = 1.4

Hence a = 1.4 and d = 6.9

How many soultions does the equation 2(p+5) = 4 - 10p have? Explain how you found your answer.

Answers

Answer:

1, p = -0.5

Step-by-step explanation:

2(p+5) = 4 - 10p

2p+10 = 4 - 10p

2p + 10p = 4 - 10

12p = -6

p = -6/12

p = -0.5

2(-0.5+5) = 4 - 10(-0.5)

-1 + 10 = 4 + 5

9 = 9

You answer 0.8 questions correctly.
a. What percent of the questions did you answer correctly?

you answer 0.8 questions correctly. what percent of the questions did you answer correctly. What fraction of the questions did you answer incorrectly? Use / for fraction and answer

Answers

Answer:

Step-by-step explanation:

Fraction:

0.8 = 8/10 = 4/5

Percent:

0.8*100 = 80%

Answer:

Solution :-

0.8 can be written as

8/10 and

Percentage = 8/10 × 100

Percentage = 8 × 10

Percentage = 80%

Or,

Simply

Percentage = 0.8 × 100

Percentage = 80%

[tex] \\ [/tex]

Please help! I'm feeling good today, I'll give you 20 points. Thanks!!

Answers

Answer:

solution:

5(4+2x)=-(x-5)-7

20+10x=-x+5-7

10x+x=-2-20

x=-22/11=-2

x=-2

so.D.-2 is your answer.

who can help me please ?​

Answers

1/x^15




*how do u do the explanation thingy*

Suppose you know the perimeter of a rectangle. How can you write

an equation for the area in terms of the length of a side?

Answers

Step-by-step explanation:

L+W+L+W=26 so 2L=26–2W and you can find length from the perimeter as L=13−W

LW=42 so L=42/W is the other way to find the length, from the area. Both ways require you to know W, but if you have both pieces of information the two answers for length must be the same 42/W=13−W, and you solve this:

42=13W−W2

W2–13W+42=0

(W−6)(W−7)=0

Either W−6=0 or  W−7=0

If a is inversely proportional to x, a=15 when x=25 find the constant of variation, k

Answers

Answer:

Step-by-step explanation:

"Inversely proportional to x" in this situation is represented by a = k/x.

Find k:

Let a = 15 and x = 25, then calculate k:

15 = k/25)

Multiplying both sides by 25 yields k = 15(25), or k = 3/5

                       3

and so a = -----------

                      5x

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