How to put 4/10 in the simplest form

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

Scale factor of 2 is used to enlarge a figure as shown below the area of is 18 in.²

Solve this system of equations. 12x − 18y = 27 4x − 6y = 10