Question:
Solve 160 = -501*i + 481*i for i..

Answer:
-8

Question:
Solve 6*s + 7*s + 13 = 0 for s..

Answer:
-1

Question:
Solve 284*f = 288*f + 4 for f..

Answer:
-1

Question:
Solve 35*t + 30*t = -260 for t..

Answer:
-4