question: Teacher asked me this: Solve 7*l + 4 = 4 for l.
++++++++++
answer: 0

question: Teacher asked me this: Solve 4*s - 54 = 13*s - 63 for s.
++++++++++
answer: 1

question: Teacher asked me this: Solve 538*r + 30 = 528*r for r.
++++++++++
answer: -3

question: Teacher asked me this: Solve -41*d + 7*d - 1469 = 2*d + 1339 for d.
++++++++++
answer:
-78