Answer: x = 35°
Steps:
(x + 10) + (3x - 5) + x = 180
x + 10 + 3x - 5 + x = 180
5x + 10 - 5 = 180
5x + 5 = 180
5x = 180 - 5
5x = 175
x = 175/5
x = 35
Check:
(x + 10) + (3x - 5) + x = 180
(35 + 10) + (3*35 - 5) + 35 = 180
45 + 100 + 35 = 180
180 = 180 ✅
