Question: What is the solution?

Solve 159 = 40*r + 182 + 257 for r.

Answer: -7

Question: What is the solution?

Solve 0 = -618*d - 1391*d + 41*d - 281424 for d.

Answer: -143

Question: What is the solution?

Solve -235*y - 2374 = 1151 for y.

Answer: -15

Question: What is the solution?

Solve -96*o + 93*o + 12 = 0 for o.

Answer:
4