B is the answer.
Simplifying 12m + 4n = 480 Solving 12m + 4n = 480 Solving for variable 'm'. Move all terms containing m to the left, all other terms to the right. Add '-4n' to each side of the equation. 12m + 4n + -4n = 480 + -4n Combine like terms: 4n + -4n = 0 12m + 0 = 480 + -4n 12m = 480 + -4n Divide each side by '12'. m = 40 + -0.3333333333n
