Q: Solve:
Solve 0 = 66*l + 53 + 13 for l.

A: -1

Q: Solve:
Solve 317 = 24*q - 243 + 80 for q.

A: 20

Q: Solve:
Solve 0 = 5*u - 15*u - 40 for u.

A:
-4