Question: What is the solution?

Solve -1590*u + 29694 = 4254 for u.

Answer: 16

Question: What is the solution?

Solve -63*r + 160*r = 84*r - 143 for r.

Answer: -11

Question: What is the solution?

Solve 42*h - 229 = 159 + 74 for h.

Answer: 11

Question: What is the solution?

Solve -231 - 174 = 12*o - 477 for o.

Answer:
6