Question: What is the solution?

Solve -10*b - 13*b = -7*b for b.

Answer: 0

Question: What is the solution?

Solve 228*f + 71*f + 8450 = -12*f - 14*f for f.

Answer: -26

Question: What is the solution?

Solve -131*j + 91 = -144*j for j.

Answer: -7

Question: What is the solution?

Solve -21*u - 424 = -110 - 125 for u.

Answer:
-9