question: Teacher asked me this: Solve -17*f = -9*f for f.
++++++++++
answer: 0

question: Teacher asked me this: Solve 344 + 401 = 67*u + 142 for u.
++++++++++
answer: 9

question: Teacher asked me this: Solve -9*w - 64 = -25*w for w.
++++++++++
answer: 4

question: Teacher asked me this: Solve 5*r - 387 = -392 for r.
++++++++++
answer:
-1