question: Teacher asked me this: Solve 105*f = -121*f + 904 for f.
++++++++++
answer: 4

question: Teacher asked me this: Solve r = 6*r + 10 for r.
++++++++++
answer: -2

question: Teacher asked me this: Solve 63 = 3*v + 51 for v.
++++++++++
answer: 4

question: Teacher asked me this: Solve 0 = -54*k + 115*k - 10*k + 714 for k.
++++++++++
answer:
-14