Q: What is the solution?
Solve 3*r = -2*r - 10 for r.

A: -2

Q: What is the solution?
Solve -315*c = -75*c + 6725 - 1685 for c.

A: -21

Q: What is the solution?
Solve 15 = -5*i - 0 for i.

A:
-3