Solve -887*a + 1511 = 64801 + 10331 for a.
Solve this plz.

A: -83

Solve 0 = 12*r + 13*r - 100 for r.
Solve this plz.

A: 4

Solve 14292 - 17412 = 208*n for n.
Solve this plz.

A:
-15