Question:
Solve -7*c = -9*c + 6 for c..

Answer:
3

Question:
Solve 330 = 102*d - 124*d for d..

Answer:
-15

Question:
Solve 0 = -874*u + 18311 - 2579 for u..

Answer:
18

Question:
Solve -5257 = -158*p - 67*p - 307 for p..

Answer:
22