Solve 0 = 3657*r + 7875*r - 1959*r + 38221 - 478579 for r.
Solve this plz.

A: 46

Solve -12*u - 136 = -18*u + 40*u for u.
Solve this plz.

A: -4

Solve 253*f - 1521 = 84*f for f.
Solve this plz.

A:
9