Question: What is the solution?

Solve -4*c = 7*c - 4*c for c.

Answer: 0

Question: What is the solution?

Solve -21*i + 870 - 681 = 0 for i.

Answer: 9

Question: What is the solution?

Solve 401*m + 1308 = -35*m for m.

Answer: -3

Question: What is the solution?

Solve 0 = 2786*z - 3402*z + 52976 for z.

Answer:
86