Question:
Solve -4*s = -7*s + 15 for s..

Answer:
5

Question:
Solve -19*b - 74 = 127 + 27 for b..

Answer:
-12

Question:
Solve 10*k = 12*k + 8 for k..

Answer:
-4

Question:
Solve 5*l = -7*l - 24 for l..

Answer:
-2