can someone double check this? I got 12 as my answer

Answer:
angle C = 69 degrees
Step-by-step explanation:
(6x - 9) + (6x - 24) + (81 - x) = 180
11x + 48 = 180
11x = 132
x = 12
(81 - 12) = 69 degrees
Answer:
69°
Step-by-step explanation:
All angles in a triangle must add to 180°:
(5x+9)+(4x+15)+(x+36)=180
10x+60=180
10x=120
x=12°
The problem asks for the measure of angle C:
C=(81-x)°=69°
You were on the right track because you got the value of x correct. You just didn't answer the problem correctly.