Since these angles are supplementary, we can say 4x + 2 + (7x + 13) = 180
Break bracket : 4x + 2 + 7x + 13 = 180
Now we group these : (4x+7x) + (2+13) = 180
11x + 15 = 180
11x = 165
x = 165/11 = 15
Now we substitute this in 4x + 2 to find the second angle :
4 x 15 + 2 = 62
We can find the missing angle : 180 - 38 - 62 = 80
