Please help i wanna want to finish this but I don't know

An architect is designing a water fountain for a park she uses the given function to model the water jet flowing from the fountain nozzles where h(x) gives the height of the water jugs in feet x feet from the starting point h(x)=-1/20x+x+15

Find the greatest common factor of -30x 4 yz 3 and 75x 4 z 2.

Simplify the expression and find the missing terms. the simplest form of has in the numerator and in the denominator.