Question

Find the equation of the parabola that passes through the given points. Contains all three points: (-2,-20);(0,- 4);(4-20)
PLEASE HELP!!

Answer 1

clearly, since f(-2) = f(4) = -20, the axis of symmetry is at x = (-2+4)/2 = 1
y = a(x-1)^2 + k
So now you have
9a+k = -20
a+k = -4
solve that and you wind up with
y = -2(x-1)^2 - 2