What are the common factors of 15, 45 and 90

On a piece of paper, graph . then determine which answer choice matches the graph you drew

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.

X+y ≥20 x≤2y a) (0,22) b) (7,11) c) ( 15,6) d) (10,10) e) (12,5) f) (8,16)