When the y-value decreases from 0 to -3, the rise is?

The tuition costs, c, for a local community college are modeled by c(h) = 250 + 200h, where h represents the number of credit hours taken. the local state university has tuition costs, s, modeled by the function s(h) = 300 + 180h. how many credit hours will a student have to take for the two tuition costs to be equal? round the answer to the nearest tenth of an hour.

Can someone tell me if this is perpendicular? !

Item 1 solve for s. s+24=90 −114 −66 66 114