Algebra 1

$\frac{1-x^4}{x-1}=-(1+x)(1+x^2)$
Given: $1-x^4$ Apply formula:$(m^2-n^2)=(m-n)(m+n)$ $1-x^4=(1-x^2)(1+x^2)$ $1-x^4=-(x-1)(1+x)(1+x^2)$ Thus, $\frac{1-x^4}{x-1}=-(1+x)(1+x^2)$