question: Teacher asked me this: Solve -13 = i - 16 for i.
++++++++++
answer: 3

question: Teacher asked me this: Solve 29*v = 27*v for v.
++++++++++
answer: 0

question: Teacher asked me this: Solve 63 = -5*b + 3*b - 5*b for b.
++++++++++
answer: -9

question: Teacher asked me this: Solve 0 = 209*u - 103*u + 586*u - 12456 for u.
++++++++++
answer:
18