A cubic function y has real coefficients, and its zeros are 5, -4 and 1. If x=-3, y=64 satisfies its equation, find the equation of the cubic function in standard form.
(x-5)(x+4)(x-1) = 0 subbing in x = -3 yields 32 so there must be a 2 multiplier
2 (x-5)(x+4)(x-1) = multiply all of this out :
Guest is correct
But maybe this will explain better where the 2 came from.
just sub in x=-3 and y=64
Solve for a
And yes you do have to expand it.