Question:
Solve 3*n - 11*n + 40 = 0 for n..

Answer:
5

Question:
Solve -45*u - 93 = -14*u for u..

Answer:
-3

Question:
Solve 0 = -19*s + 9973 - 9536 for s..

Answer:
23

Question:
Solve -2*r + 3 = -5*r for r..

Answer:
-1