Q: What is the solution?
Solve 91*a = 33 + 877 for a.

A: 10

Q: What is the solution?
Solve -16*r = 20*r - 324 for r.

A: 9

Q: What is the solution?
Solve -261 - 693 - 1092 - 1764 = 381*l for l.

A:
-10