Hey i have an exam tomorrow in my "statistics for computer science" course and i need on a few problems.. not sure where to start on them..

screenshot of the first two below.. in advance

Write numerical coefficient of y² in the expression 2x² - 15xy – 7y²

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.

Simplify the expression 10/11(22z) + (a+5) -1