question: Teacher asked me this: Solve -419*a = -421*a - 6 for a.
++++++++++
answer: -3

question: Teacher asked me this: Solve -73*v + 10162 = 8775 for v.
++++++++++
answer: 19

question: Teacher asked me this: Solve -141*a = -147*a for a.
++++++++++
answer: 0

question: Teacher asked me this: Solve 7*k = -0*k - 21 for k.
++++++++++
answer:
-3