Question

For the solution (x, y) to the system of equations, what is the value of x − y?

7x + 3y = 8
6x − 3y = 5
A) −
4
3
B)
2
3
C)
4
3
D)
22
3

Answer 1

x = 1 y = 1/3

Explanation:

STEP 1) get the equations to equal each other

7x + 3y = 8 6x - 3y = 5

- 7x - 6x

3y = 8 - 7x -3y = 5 - 6x

*1 *-1

3y = 8 - 7x = 3y = -5 + 6x

STEP 2) solve for x

8 - 7x = 6x - 5

+7x

8 = 13x - 5

+5

13 = 13x

/13

1 = x

STEP 3) use x to solve for y

7x + 3y = 8

=

7 + 3y = 8

-7

3y = 1

/3

y = 1/3