Calculate the number in the middle of 1.5 and 7.1​

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

Through: (-3,-3) parallel to y= 7/3x+3

Solve the system of equations using the substitution method. {y=−3x+7x=−2y−16 enter your answers in the boxes.