Question: What is the solution?

Solve 0 = -80*u + 485 + 75 for u.

Answer: 7

Question: What is the solution?

Solve 28*l - 96*l = -1473 + 249 for l.

Answer: 18

Question: What is the solution?

Solve -5693*s - 2375*s = -777*s + 406*s + 130849 for s.

Answer: -17

Question: What is the solution?

Solve -390*x = -283*x + 749 for x.

Answer:
-7