Q: Solve:
Solve -389*r - 391 = 2*r for r.

A: -1

Q: Solve:
Solve 35 = 20*y + 15 for y.

A: 1

Q: Solve:
Solve 574919 = 15558*v - 253427 + 191053 - 467325 for v.

A:
71