question: Teacher asked me this: Solve 5*s + 63 - 43 = 0 for s.
++++++++++
answer: -4

question: Teacher asked me this: Solve -270 = 49*z + 216 - 143 for z.
++++++++++
answer: -7

question: Teacher asked me this: Solve 17*k + 3 = 16*k for k.
++++++++++
answer: -3

question: Teacher asked me this: Solve 13*u - 20 = 3*u for u.
++++++++++
answer:
2