Question

If 4x - 3y = -18 and 6x + 7y = -4, then what is the value of y?

Answer 1

y = 2

Explanation:

4x - 3y = -18, then 4x = 3y - 18, x = (3y - 18)/4

6x + 7y = -4

substitute for x:

6((3y - 18)/4) + 7y = -4

(18y - 108)/4 + 7y = -4

4.5y - 27 + 7y = -4

combine like terms:

11.5y = 23

y = 2

check:

x = (3(2) - 18)/4 = -12/4 = -3

6(-3) + 7(2) = -4

-18 - 14 - -4

-4 = -4

so y = 2 is correct