First we need to write the factors of the polynomial. In order for 1, 4, and -3 to be roots, they need to be the x values that make the polynomial equal 0.
(x - 1) = 0
That would be the factor for x = 1 because when we plug 1 in for x we get 1 - 1 which equals 0.
Multiply all the factors together.
(x-1)(x-4)(x+3)=0
Now FOIL.
[tex](x^2-5x+4)(x+3)[/tex]
[tex]x^3-2x^2-11x+12[/tex]