Question 147925
We know the sum of the angels in a triangle is 180.

Given: A = 2B + 20
Then C = 180 - A - B
C = 180 - (2B+20) - B
C = 180 - 2B - 20 - B
C = 160 - 3B

So, the angles are:
A = 2B+20
B = B
C = 160 - 3B

Make sense?