Question: What is the solution?

Solve 91*c - 30 + 72 + 413 = 0 for c.

Answer: -5

Question: What is the solution?

Solve 56*m - 23*m = -33 for m.

Answer: -1

Question: What is the solution?

Solve 0 = -39*d + 314 + 37 for d.

Answer: 9

Question: What is the solution?

Solve 207*c + 12640 = -425*c for c.

Answer:
-20