\(x->a\left(please\right)\)
\(a^2+a-6=a^2+3a-2a-6=a\left(a+3\right)-2\left(a+3\right)=\left(a-2\right)\left(a+3\right)\)
\(a^4+a^2+2a=\left(a^4-1\right)+\left(a^2+2a+1\right)=\left(a^2+1\right)\left(a-1\right)\left(a+1\right)+\left(a+1\right)^2=\left(a+1\right)\left(a^3-a^2+a\right)=a\left(a+1\right)\left(a^2-a+1\right)\)