Question: What is the solution?

Solve 278 - 30 = 13*u - 77 for u.

Answer: 25

Question: What is the solution?

Solve 112*m - 6601 = -1785 for m.

Answer: 43

Question: What is the solution?

Solve -51*d = -1072*d - 9902 - 14602 for d.

Answer: -24

Question: What is the solution?

Solve 0 = 42*k + 260 + 250 + 582 for k.

Answer:
-26