Question:
Solve 21 = -5*w + 11 for w..

Answer:
-2

Question:
Solve -76*h = -33*h - 36*h - 84 for h..

Answer:
12

Question:
Solve 167*z = -403*z + 4294 - 13414 for z..

Answer:
-16

Question:
Solve -6*z - 4 = 2 for z..

Answer:
-1