## Introductory Algebra for College Students (7th Edition)

$4x$
RECALL: The perfect square trinomial $a^2-2ab+b^2$ can be factored using the formula: $a^2-2ab+b^2=(a-b)^2$ The given trinomial can be written as: $=(4x0^2-2(4x)(3)+3^2$ This trinomial above is a perfect square trinomial which can be factored using the formula given above. Factor using the formula above with $a=4x$ and $b=3$ to obtain: $=(4x-3)^2$ Thus, the missing expression in the given statement is: $4x$