Question

Use the linear combination method to solve this system of equations. What is the value of x?

3x + 7y = 31
-3x - 2y =-1

A) -6
B) -3 2/3
C) 3 2/3
D) 6

Answer 1

B

Explanation:

Edge2020

Answer 2

For this case we have the following system of equations:

`3x + 7y = 31\\-3x-2y = -1`

We multiply the first equation by 2:

`6x + 14y = 62`

We multiply the second equation by 7:

`-21x-14y = -7`

We add the equations:

`6x-21x + 14y-14y = 62-7\\-15x = 55\\x = \frac {55} {- 15}\\x = -3.67`

We convert to a mixed number:

`x = - 3 \frac {2} {3}`

Answer:

The value of x is
`- 3 \frac {2} {3}`

Option B