What’s the answer please ?

Find the product of (4x + 3y)(4x − 3y). 16x2 − 24xy + 9y2 16x2 − 9y2 16x2 + 24xy + 9y2 16x2 + 9y2

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.

Need solving this second acceleration problem.