a) We know, sum of all the angles in a triangle is equal to 180
So, 35 + 52 + 3(x+2) = 180
87 + 3x + 6 = 180
3x + 93 = 180
3x = 180 - 93
x = 87/3
x = 29
In short, Your Answer for this part would be 29
b) Angle C = 3(x + 2)
Substitute the value of x,
C = 3(29 + 2)
C = 3(31)
C = 93
In short, Your Answer would be 93
Hope this helps!
