question: Teacher asked me this: Solve -21*o + 1 + 20 = 0 for o.
++++++++++
answer: 1

question: Teacher asked me this: Solve 0 = -0*w + 4*w - 4 for w.
++++++++++
answer: 1

question: Teacher asked me this: Solve -981*r + 887*r = 2184*r + 52394 for r.
++++++++++
answer: -23

question: Teacher asked me this: Solve -12 = -2*f - 4 for f.
++++++++++
answer:
4