Answer:
x=57
Step-by-step explanation:
The sum of the angles of a triangle add to 180 degrees
(x-5) + (2x-7) + 21 = 180
Combine like terms
3x +9 = 180
Subtract 9 from each side
3x+9-9= 180-9
3x = 171
Divide by 3
3x/3 =171/3
x =57
