Question:
Solve -3 = -4*k - 7 for k..

Answer:
-1

Question:
Solve -s - 11 = -5 for s..

Answer:
-6

Question:
Solve 10*q - 80 - 21 = 193 + 186 for q..

Answer:
48

Question:
Solve -100*w = -99*w - 6 for w..

Answer:
6