A I think I am not 100% right
Yes because 84+45 is 129 and 3(28+15) is 129
So we have the equation:

Then we need to multiply by 4 on both sides to get rid of the denominator on the left:

Then we subtract 9 on both sides to solve for z:

Therefore the answer is z = -0.6.
Answer:
73
Step-by-step explanation:
90-17=x
x=73