Question: What is the solution?

Solve 148 = -13*s + 50*s for s.

Answer: 4

Question: What is the solution?

Solve -6300 + 4299 = 87*d for d.

Answer: -23

Question: What is the solution?

Solve 157 = -8*t + 141 for t.

Answer: -2

Question: What is the solution?

Solve 91*r + 314*r = 3557*r - 387696 for r.

Answer:
123