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2 years ago

Trevor solved the system of equations below. What mistake did he make in his work?

1 answer:

3 0

The answer is He subtracted 10 from the right side instead of adding 10 to the right side

Let's solve it:
2x + y = 5
x − 2y = 10
________
Rearrange first equation to get y:
y = 5 - 2x
________
Substitute y into the second equation:
x - 2(5 - 2x) = 10
________
Multiply the terms:
x - 10 + 4x = 10
________
Combine the terms:
5x - 10 = 10
________
Add 10 on the both sides of the equation:
5x = 10 + 10
5x = 20
x = 4

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Isolate the variable to find the solution of the equation. 6.2w = 18.6 w = 3 w = 12.4 w = 24.8 w = 115.32

iragen [17]

6.2w = 18.6....divide both sides by 6.2
w = 18.6 / 6.2
w = 3 <==

3 0

2 years ago

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Consider the following equations and name the property of equality used to solve for the variable.

Viktor [21]

9514 1404 393

Answer:

A. subtraction

B. division

C. multiplication

D. addition

Step-by-step explanation:

Observe what is done to the variable. Choose the operation that turns the unwanted value into the appropriate identity element.

A. 3.75 is added. To make that value be 0, we subtract 3.75.

B. -3 is multiplied. To make that value be 1, we divide by -3.

C. m is divided by 5. To make that 1/5 multiplier be 1, we multiply by 5.

D. 4 is subtracted. To make that value be zero, we add 4.

_____

Additional comment

Since subtraction is the same as addition of the opposite, and division is the same as multiplication by the reciprocal, the only two properties we really need are the addition property and multiplication property. Your grader may disagree.

5 0

3 years ago

Please help im really confused Which expression is equivalent to 4(7 + 8)?

Hatshy [7]

Answer:

With the answer choices:

A. 11 + 8

B. 11 + 12

C. 28 + 12

D. 28 + 32

The answer would be 28+32.

Step-by-step explanation:

Use the distributive law.

4 * 7 = 28

4 * 8 = 32

Hope this helps!

8 0

2 years ago

18. Determine the common difference, the fifth term, and the sum of the first 100 terms of the following sequence:

Ksenya-84 [330]

$a_1=1,\ a_2=2.5,\ a_3=4,\ a_4=5.5,\ ...\\\\a_2-a_1=2.5-1=1.5\\a_3-a_2=4-2.5=1.5\\a_4-a_3=5.5-4=1.5\\a_{n+1}-a_n=1.5=constans\\\\\text{It's an arithmetic sequence with}\\a_1=1,\ \boxed{d=1.5}\\\\a_n=a_1+(n-1)d\to a_n=1+(n-1)(1.5)=1+1.5n-1.5\\\\a_n=1.5n-0.5\\\\a_5=1.5(5)-0.5=7.5-0.5=7\\\boxed{a_5=7}\\\\\text{The formula of a Sum of the First n Terms of an Arithmetric Sequence:}\\\\S_n=\dfrac{2a_1+(n-1)d}{2}\cdot n\\\\\text{We have:}\\a_1=1,\ d=1.5,\ n=100\\\\\text{Substitute}$

$S_{100}=\dfrac{(2)(1)+(100-1)(1.5)}{2}\cdot100=\dfrac{2+(99)(1.5)}{1}\cdot50\\\\=(2+148.5)\cdot50=150.5\cdot50=7,525\\\\\boxed{S_{100}=7,525}\\\\Answer:\\the\ common\ difference:\ d=1.5\\the\ fifth\ term:\ a_5=7\\the\ sum\ of\ first\ 100\ terms:\ S_{100}=7,525$

8 0

3 years ago

X - y = 2 4x – 3y = 11

swat32

Answer:

For x - y = 2

You need to find x or y in one of the equations and then substitute that into the other.

So we have;

x-y=2

4x-3y=11

We will take the first equation and find x;

x-y=2

add y to both sides;

x-y+y=2+y

x=2+y

Now we take that answer and substitute it forx in the other equation;

4(2+y)-3y=11

8+4y-3y=11

8+y=11

y=3

Now we have what y equals, so we use it in the first equation to find x;

x-3=2

x=5

So we have;

x=5; y=3

Hope you understand!

And for 4x – 3y = 11

Multiply the first equation by 2 and the second by 3 so that there are the same number of y's in each:

8x - 6y = 22 ...(3)

30x + 6y = -3 ...(4)

Now add (3) and (4) term by term:

38x + 0 = 19

38x = 19

or x = 1/2

Put this back into equation (1)

4*(1/2) - 3y = 11

2 - 3y = 11

Subtract 2 from both sides:

-3y = 9

Divide both sides by -3

y = -3

6 0

2 years ago

Read 2 more answers