Starting with x=1, subtract 1 from each side,
(x-1)=0
Our polynomial will have multiplicity of 2 for this particular zero,
(x-1)(x-1)
and do similar with the x=-4, add 4 to each side,
(x+4)=0
So our final result is: (x-1)(x-1)(x+4)
Expand out the brackets if you need this in standard form.
