## Elementary and Intermediate Algebra: Concepts & Applications (6th Edition)

$x^2-8x^4+16x^6$
Using $(a+b)^2=a^2+2ab+b^2$ or the square of a binomial, the given expression, $\left( x-4x^3 \right)^2$, is equivalent to \begin{array}{l}\require{cancel} (x)^2+2(x)(-4x^3)+(-4x^3)^2 \\\\= x^2-8x^4+16x^6 .\end{array}