Find a formula for the polynomial P(x)

Question

degree:3

root of multiplicity 2 at x=4

root of multiplicity 1 at x=-1

y-intercept (0,9.6)

Answer 1

a(x-4)^2(x+1)

=a(x^2 - 8x + 16)(x+10)

= (9.6/160)(x^3 +2x^2 -64x + 160)

= 9.6x^3/160 + 19.2x^2/160 - 614.4x/160 + 9.6

= .06x^3 + .12x^2 - 3.84x + 9.6