Line m is represented by the following equation: x − y = 8

which equation completes the system that is satisfied by the solution (18, 10)?

2x-y=26
x+t=18
2x-2y=36
x-y=-28

Let's plug in (18,10) into each answer choice until we find the one that has it as a solution.

A) 2x - y = 26
2(18) - 10 = 26
36 - 10 = 26
26 = 26

Your answer is A.

I'll just do the rest to show that you the they are incorrect.

B) x + y = 18
18 + 10 = 18
28 ≠ 18

C) 2x - 2y = 36
2(18) - 2(10) = 36
36 - 20 = 36
16 ≠ 36

D) x - y = -28
18 - 10 = -28
8 ≠ -28

Your answer is A) 2x - y = 26.