Solve 23*o - 123 = 15 for o.
Solve this plz.

A: 6

Solve 200*f - 256 - 529 = 1255 + 360 for f.
Solve this plz.

A: 12

Solve 40 = 4*b + 44 for b.
Solve this plz.

A:
-1