## Elementary Algebra

$64x^3-x$
Using $(a-b)(a+b)=a^2-b^2$, or the product of the sum and difference of like terms, the given expression, $x(8x+1)(8x-1) ,$ is equivalent to \begin{array}{l}\require{cancel} x[(8x)^2-(1)^2] \\\\= x(64x^2-1) .\end{array} Using the Distributive Property, the expression, $x(64x^2-1) ,$ is equivalent to \begin{array}{l}\require{cancel} 64x^3-x .\end{array}