Question 757610
{{{x^2 – x – (2k + 2)=0}}}

if {{{x=-4}}}

{{{(-4)^2 – (-4) – (2k + 2)=0}}}

{{{16 +4 – 2k- 2=0}}}

{{{16 +4-2=2k}}}

{{{18=2k}}}

{{{18/2=k}}}

{{{highlight(k=9)}}}

{{{x^2-x -(2k + 2)=0}}}........plug in {{{highlight(k=9)}}}

{{{x^2-x -(2*9 + 2)=0}}}

{{{x^2-x -(18 + 2)=0}}}

{{{x^2-x -20=0}}}


{{{ graph( 600, 600, -10, 10, -10, 10,x^2-x-20) }}}


as you can see, {{{-4}}} is a zero of the polynomial {{{x^2-x-20=0}}}