Question: What is the solution?

Solve 2*m = -2*m + 4 for m.

Answer: 1

Question: What is the solution?

Solve 2 = 4*k - 2 for k.

Answer: 1

Question: What is the solution?

Solve -108 = -7*d - 129 for d.

Answer: -3

Question: What is the solution?

Solve -2792*u + 10713 = 1987*u + 712*u - 450531 for u.

Answer:
84