Question: What is the solution?

Solve 3*k = 1213 - 1228 for k.

Answer: -5

Question: What is the solution?

Solve 100*u - 126 + 76 = 250 for u.

Answer: 3

Question: What is the solution?

Solve -5*a = -0*a for a.

Answer: 0

Question: What is the solution?

Solve 84 = -2*r + 70 for r.

Answer:
-7