Answer:
x=13
Step-by-step explanation:
The two angles form a straight line so they add to 180 degrees
9x+17 + 3x+7 = 180
Combine like terms
12x +24 =180
Subtract 12 from each side
12x+24-24 =180-24
12x =156
Divide each side by 12
12x/12 =156/12
