Answer:
B. y = 16.
Step-by-step explanation:
x = 20 - y
7x - 12 = y
Rearranging both equations
x + y = 20..............A
7x - y = 12..............B Adding A + B:
8x + 0 = 32
x = 32/8 = 4.
Substituting x = 4 in equation A:
4 + y = 20
y = 16.
Checking the results in the original equations:
x = 20 - y
4 = 20 - 16 = 4 Checked.
7x - 12 = y
7(4) - 12 = 16
28 - 12 = 16 Checked.
