Q: What is the solution?
Solve -41*k + 39*k = 2 for k.

A: -1

Q: What is the solution?
Solve 0 = -634*u + 420 - 1688 for u.

A: -2

Q: What is the solution?
Solve 0 = 2*o + 19 - 17 for o.

A:
-1