Question: What is the solution?

Solve -391*s + 86 = -158*s + 319 for s.

Answer: -1

Question: What is the solution?

Solve -8102*k - 9715 = -8247*k for k.

Answer: 67

Question: What is the solution?

Solve -5*f = 53 - 38 for f.

Answer: -3

Question: What is the solution?

Solve -890*k = -1060*k - 5950 for k.

Answer:
-35