question: Teacher asked me this: Solve -786*s = -778*s + 56 for s.
++++++++++
answer: -7

question: Teacher asked me this: Solve 1384*l - 470*l = -615*l - 16819 for l.
++++++++++
answer: -11

question: Teacher asked me this: Solve -78*r + 431 + 634 = -105 for r.
++++++++++
answer: 15

question: Teacher asked me this: Solve 864*l + 19791 = -5265 for l.
++++++++++
answer:
-29