Explanation:
Find x :
(x) + (x + 25) + (x + 35) = 180
x + x + x = 180 - 25 - 35
3x = 120
x = 120/3
x = 40°
And then, find q and substitute a value of x :
3q + q + x = 180
4q + 40 = 180
4q = 180 - 40
4q = 140
q = 140/4
q = 35°
Last, find p and substitute a value of x :
p + (x + 35) + (x + 25) = 180
p + (40 + 35) + (40 + 25) = 180
p + 75 + 65 = 180
p + 140 = 180
p = 180 - 140
p = 40°