Answer:
see below
Step-by-step explanation:
The interior angle of the triangle on the right is 180 - ( 9x+12)
this plus the other two sum to 180 degrees
180 - (9x+12) + 4x-3 + 6x + 3 = 180
x = 12
then the angles are 6(12) + 3 = 75 4(12) -3 = 45 and 60°
