Question:
Solve 10 = -23*s + 21*s for s..

Answer:
-5

Question:
Solve -3*z - 125 + 122 = 0 for z..

Answer:
-1

Question:
Solve 0 = 4*o + 9 + 3 for o..

Answer:
-3

Question:
Solve 21*j - 4 - 11 = -78 for j..

Answer:
-3