Answer :
Use the remainder theorem; dividing a polynomial [tex]p(x)[/tex] by [tex]x-c[/tex] leaves a remainder equal to [tex]p(c)[/tex]. Here
[tex]p(x)=x^4+6x^3+7x^2-6x-8[/tex]
[tex]\implies p(c)=(-4)^4+6(-4)^3+7(-4)^2-6(-4)-8=\boxed{0}[/tex]
Use the remainder theorem; dividing a polynomial [tex]p(x)[/tex] by [tex]x-c[/tex] leaves a remainder equal to [tex]p(c)[/tex]. Here
[tex]p(x)=x^4+6x^3+7x^2-6x-8[/tex]
[tex]\implies p(c)=(-4)^4+6(-4)^3+7(-4)^2-6(-4)-8=\boxed{0}[/tex]