Answer: (4) x = 15
Steps:
1. Isolate y in the equation x - y = 4
x - y = 4
-y = 4 - x
y = 4 - x / -1
2. Substitute value of x (15) into the new equation y = 4 - x / -1
y = 4 - 15 / -1
y = -11 / -1
y = 11
3. Plug in your y value (11) and x value (15) into the equation x + 2y = 37
15 + 2(11) = 37
15 + 22 = 37
37 = 37 ✅
4. Plug in your y value (11) and x value (15) into the equation x - y = 4
15 - 11 = 4
4 = 4 ✅
both equations are true with the value of x being 15 therefore your answer is
(4) x = 15