question: Teacher asked me this: Solve -309*s + 6322 = 559*s - 12774 for s.
++++++++++
answer: 22

question: Teacher asked me this: Solve r = -25*r + 78 for r.
++++++++++
answer: 3

question: Teacher asked me this: Solve -81*f = -63*f for f.
++++++++++
answer: 0

question: Teacher asked me this: Solve -11*i - 20*i - 117 = 38 for i.
++++++++++
answer:
-5