Question:
Solve -116*c + 99*c = 90*c + 321 for c..

Answer:
-3

Question:
Solve -376*f - 1967 + 5543 = -4320 for f..

Answer:
21

Question:
Solve -3*u + 21 = 12 for u..

Answer:
3

Question:
Solve -956*r - 15920 = -5404 for r..

Answer:
-11