Help Please.

Question

A wireless phone company offers two plans. In one plan, there is a monthly fee of $40 and a charge of $0.25 per minute. In the other plan, there is monthly fee of $25 and a charge of $0.40 per minute. For what number of minutes are the costs equal?

Answer 1

In order, these equations are:
1) .25x + 40
2) .40x + 25
Where the charge per minute is the slope, the flat rate the y-intercept.

We want to know for what number of minutes these two plans cost the same, so set equations (1) and (2) equal to each other and solve for x.