Answer:
x = 4
Explanation:
Given the 2 equations
2x + y = 7 → (1)
x - y = 5 → (2)
Rearrange (1) expressing y in terms of x by subtracting 2x from both sides
y = 7 - 2x ← substitute into (2)
x - (7 - 2x) = 5
x - 7 + 2x = 5, that is
3x - 7 = 5 ( add 7 to both sides )
3x = 12 ( divide both sides by 3 )
x = 4