question: Teacher asked me this: Solve -309*d + 50 = -319*d for d.
++++++++++
answer: -5

question: Teacher asked me this: Solve -9*d = 12*d - 24*d for d.
++++++++++
answer: 0

question: Teacher asked me this: Solve -965 + 935 = -3*r for r.
++++++++++
answer: 10

question: Teacher asked me this: Solve -1801*a - 8716 - 11861 - 8239 = 0 for a.
++++++++++
answer:
-16