Q: What is the solution?
Solve 36*d - 225 = -9*d for d.

A: 5

Q: What is the solution?
Solve -168*r = 42*r - 3363 + 213 for r.

A: 15

Q: What is the solution?
Solve 14*f - 401 = 3*f - 368 for f.

A:
3