Question:
Solve 7*y - 21*y - 12*y = 0 for y..

Answer:
0

Question:
Solve 0 = -14*s - 48 - 22 for s..

Answer:
-5

Question:
Solve 2106*y = 2147*y - 164 for y..

Answer:
4

Question:
Solve 641*g - 806 = 667*g for g..

Answer:
-31