Answer:
x=27
Step-by-step explanation:
3x+9 is a right angle because 3x+9 + a right angle make a straight line
3x+9 +90 = 180
Subtract 90 from each side
3x+9 = 90
We now can solve for x
3x+9-9 = 90-9
3x = 81
Divide each side by 3
3x/3 = 81/3
Answer: 27
(3x +9) is on a straight line with the right angle so we know
3x+9= 90
So
x = 27
