Question: What is the solution?

Solve 55*n = 25*n + 29*n + 21*n - 640 for n.

Answer: 32

Question: What is the solution?

Solve 15*t + 87 = 12 for t.

Answer: -5

Question: What is the solution?

Solve -134 = -16*i + 69*i + 661 for i.

Answer: -15

Question: What is the solution?

Solve -70*r - 55315 = -189*r - 644*r - 732*r for r.

Answer:
37