Question: What is the solution?

Solve -22*r - 178 = 20 for r.

Answer: -9

Question: What is the solution?

Solve -3 = 3*d - 6*d for d.

Answer: 1

Question: What is the solution?

Solve -234*c = -276*c - 504 for c.

Answer: -12

Question: What is the solution?

Solve 1620 = 64*i + 116*i for i.

Answer:
9