The non-repeated root of $x^3+4x^2+5x+2=0$  is

$\left(x+1\right)\left(x^2+3x+2\right)=0$

$\left(x+1\right)\left(x+2\right)\left(x+1\right)=0$

$x=-1,-2,-1$

$\therefore$ So non-repeated root is $-2$ .