PLEASE HELP ME WITH MY MATH!!

The equation respenting the left table is

The equation x2 – 1x – 90 = 0 has solutions {a, b}. what is a + b?

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.