Question:
Solve 215*v - 405*v = 13680 for v..

Answer:
-72

Question:
Solve -196*r + 75*r - 66*r - 4675 = 0 for r..

Answer:
-25

Question:
Solve -112*a = -115*a - 12 for a..

Answer:
-4

Question:
Solve 0 = 68*h + 25 + 315 for h..

Answer:
-5