Answer:
x=20
Step-by-step explanation:
The two angles add together to form a straight line, which is 180 degrees.
7x + (x+20) = 180
Combine like terms
8x+20 = 180
Subtract 20 from each side
8x+20-20 = 180-20
8x =160
Divide each side by 8
8x/8 = 160/8
x = 20
