Solve -85*r + 4 = -87*r for r.
Solve this plz.

A: -2

Solve 16693 = 3322*u - 105908 - 392 - 46429 for u.
Solve this plz.

A: 51

Solve 30905 = 32612*u - 33495*u for u.
Solve this plz.

A:
-35