Q: Solve:
Solve 6*q + 13*q - 66 = -28 for q.

A: 2

Q: Solve:
Solve -1471*a + 15283 = -36202 for a.

A: 35

Q: Solve:
Solve -586*r + 1011*r - 598*r - 15743 = 0 for r.

A:
-91