Question: What is the solution?

Solve -7 = 5*f + 3 for f.

Answer: -2

Question: What is the solution?

Solve 499*k + 124 = 623 for k.

Answer: 1

Question: What is the solution?

Solve 18*i = -20*i + 228 for i.

Answer: 6

Question: What is the solution?

Solve 0 = -45*f - 1042 + 399 - 257 for f.

Answer:
-20