Q: Solve:
Solve 30*d = -206 + 386 for d.

A: 6

Q: Solve:
Solve 0 = 1261*d - 5473*d - 2063*d - 696525 for d.

A: -111

Q: Solve:
Solve 3780*r + 13632 + 68148 + 39180 = 0 for r.

A:
-32