(-2,0) and ( 4,0)
These must be the roots of the quadratic...so we have that
y = a ( x + 2) ( x - 4) simplify
y = a (x^2 - 2x - 8)
And since 54 is a max, then using symmetry, the point ( [-2 + 4]/2, 54) = (1,54) must be on the graph
So
54 = a ( 1^2 - 2(1) - 8)
54 = a (-9)
a = -54/9 = -6
So.....the function is
y = (-6) ( x^2 -2x - 8)
y = -6x^2 + 12x + 48
Here's a graph : https://www.desmos.com/calculator/s8dqi0vdcn
