Q: Solve -9 - 9 + 18 = -4*c for c.

A: 0

Q: Solve -5147*z + 18282 = -4870*z for z.

A: 66

Q: Solve 30 = -29*r + 79*r - 40*r for r.

A: 3

Q: Solve 8645 = 12*b + 8633 for b.

A:
1