Question: What is the solution?

Solve 29*b - 630 = 71*b for b.

Answer: -15

Question: What is the solution?

Solve -12 = -14*c + 20*c for c.

Answer: -2

Question: What is the solution?

Solve 5*u - 19 = -9 for u.

Answer: 2

Question: What is the solution?

Solve 326*r - 43337 + 49205 = 0 for r.

Answer:
-18