Question

Please Help!!!

Answer 1

By synthetic division,

-5  |  1    -6    -42    79
.    |        -5     55   -65
- - - - - - - - - - - - - - - - - 
.    |  1   -11    13    14

$\implies\dfrac{x^3-6x^2-42x+79}{x+5}=x^2-11x+13+\dfrac{14}{x+5}$
$\implies x^3-6x^2-42x+79=(x^2-11x+13)(x+5)+14$

When $x=-5$, you're left with a remainder of 14.