Solve -91*r - 109*r = -68*r + 660 for r.
Solve this plz.

A: -5

Solve 294*z - 312*z + 108 = 0 for z.
Solve this plz.

A: 6

Solve -8*s - 8 = -4*s for s.
Solve this plz.

A:
-2