Question

Solve the system of equations: what is the y-value in the solution?

3x - 5y = -16 and 2x + 5y = 31
A. 5
B. 3
C. 2
D. 4

Answer 1

By adding the two equations we get the x - value. Afterwards we simply substitute the computed x-value to any of the two given equations obtain the y-value.

3x - 5y = -16 (eq. 1)
2x + 5y = 31 (eq. 2)

5x = 15
x = 3

Let's try substituting x = 3 to the first eq. 1 to obtain y-value
3(3) - 5y = -16
9 - 5y = -16
-5y = -25
y = 5. (y-value is 5)

You will get the same y-value if you insert x = 3 to eq. 2

Answer 2

thank you