Question: What is the solution?

Solve -39*u - 3822 = 16*u + 140*u - 13*u for u.

Answer: -21

Question: What is the solution?

Solve -181*d - 6702 = -6637 - 8210 for d.

Answer: 45

Question: What is the solution?

Solve 130*n + 780 + 188 + 1669 + 93 = 0 for n.

Answer: -21

Question: What is the solution?

Solve -4333 = -2067*r - 12601 for r.

Answer:
-4