Solve 285 = -74*m + 9*m - 560 for m.
Solve this plz.

A: -13

Solve -326394*o + 325829*o - 3955 = 0 for o.
Solve this plz.

A: -7

Solve 333 - 893 = 51*f + 511 for f.
Solve this plz.

A:
-21