(x-5)^2-4=3(y+2)^2, (x-5+2)(x-5-2)=3(y+2)^2, (x-3)(x-7)=3(y+2)^2, (y+2)^2=(x-3)(x-7)/3, y+2=+sqrt((x-3)(x-7)/3). If x=3 or 7, y+2=0 and y=-2; if x=9, y+2=+sqrt(6*2/3)=+2, so y=-2+2 and y=-4 or 0; if x=19, y+2=+sqrt(16*12/3)=+sqrt(64)=+8, so y=-10 or 6. In general y=-2+sqrt((x-3)(x-7)/3). A graph will show the values of y for all values of x apart from 3<x<7.