Question 139966
the first two points have the same y-coordinate, so the axis of symmetry is a vertical line (x=?) midway between them
__ x=(-2+4)/2 __ x=1


the y value of the first two points is zero, so these are the roots of the quadratic equation
__ if -2 and 4 are roots, then x+2 and x-4 are factors
__ there may also be a constant factor that is related to the shape of the graph


y=k(x+2)(x-4) __ using the 3rd point __ 14=k(5+2)(5-4) __ 2=k
__ so y=2(x+2)(x-4)


the line through one point passes through the vertex, which lies on the axis of symmetry
__ substituting __ y=2(1+2)(1-4) __ y=-18