Q: Solve:
Solve -1215*l + 645 = -1172*l for l.

A: 15

Q: Solve:
Solve -1209*z + 55024 + 49767 = 1228*z for z.

A: 43

Q: Solve:
Solve 112 = 4409*j - 4417*j for j.

A:
-14