Question: What is the solution?

Solve -4*z = -9*z + 40 for z.

Answer: 8

Question: What is the solution?

Solve 47*f = 43*f + 4 for f.

Answer: 1

Question: What is the solution?

Solve -94*i = -115*i + 28 + 56 for i.

Answer: 4

Question: What is the solution?

Solve 69*u - 90*u - 422 = -174*u + 190 for u.

Answer:
4