Respuesta :

2x + (y + x) = 180 [Supplementary angles]
2x + y + x = 180
3x + y = 180 ---------- (1)

(y + x) + (y - x) = 180 [Supplementary angles]
y + x + y - x = 180
2y = 180 
y = 90 --------------- sub into (1)

3x + 90 = 180
3x = 90
x = 30

Ans: x = 30, y = 90