Question 848838
x = 0  ----> x
x = 1  ----> x-1
x=-1  ------> x+1
x=4   ------>x-4

{{{x*(x-1)*(x+1)*(x-4)}}}

{{{x^4 - 4x^3 -x^2 + 4x}}}

We need x^2 to have coefficient 7, but we have -1. So multiply the entire polynomial -7.

{{{-7x^4+28x^3+7x^2-28x}}}