F.4 Maths Variations

z=p+q
=kx+c/(y^0.5) where k and c are constants

when x=3,y=4,z=24
24=3k+c/2

when x=-1,y=36,z=0
0=-k+c/6
k=c/6

combine two equations,
c=24 and k=4
so z=4x+24/(y^0.5)

put z=24 and y=16
24=4x+24/4
so x=4.5