Question:
Solve 578*o - 673*o - 1425 = 0 for o..

Answer:
-15

Question:
Solve 744*u + 8 = 742*u for u..

Answer:
-4

Question:
Solve 77*r + 87*r - 51*r + 67*r = -3420 for r..

Answer:
-19

Question:
Solve 2457*s - 86*s - 18968 = 0 for s..

Answer:
8