Answer:
x = 12
Explanation:
The exterior angle is equal to the sum of the opposite interior angles.
5x+20 = 20 + 6x-12
Combine like terms.
5x+20 = 6x +8
Subtract 5x from each side.
5x+20-5x = 6x+8-5x
20 = x+8
Subtract 8 from each side.
20-8 = x+8-8
12 =x