Q: Solve 165 = -45*z - 285 for z.

A: -10

Q: Solve -21*m = -17*m for m.

A: 0

Q: Solve 1880 = -304*y + 210*y for y.

A: -20

Q: Solve 820*s = 900*s + 240 for s.

A:
-3