Q: Solve:
Solve 4*r = 1 - 1 for r.

A: 0

Q: Solve:
Solve -2906*k - 876*k = 1833*k - 251*k + 429120 for k.

A: -80

Q: Solve:
Solve 12063*p = 12108*p + 45 for p.

A:
-1