question: Teacher asked me this: Solve -2*x - 30 = -20 for x.
++++++++++
answer: -5

question: Teacher asked me this: Solve 0 = -395*i + 170*i - 4725 for i.
++++++++++
answer: -21

question: Teacher asked me this: Solve -2*r + 5 = 9 for r.
++++++++++
answer: -2

question: Teacher asked me this: Solve -66 = -31*y + 64*y for y.
++++++++++
answer:
-2