Answer
$4y^2-9z^2+6xz-x^2$
Work Step by Step
Use special products to multiply the given expression, $
[2y+(3z-x)][2y-(3z-x)]
.$
Using $(a+b)(a-b)=a^2-b^2$ or the product of the sum and difference of like terms, the product of the expression above is
\begin{array}{l}\require{cancel}
(2y)^2-(3z-x)^2
\\\\=
4y^2-(3z-x)^2
.\end{array}
Using $(a+b)^2=a^2+2ab+b^2$ or the square of a binomial, the product of the expression above is
\begin{array}{l}\require{cancel}
4y^2-[(3z)^2+2(3z)(-x)+(-x)^2]
\\\\=
4y^2-[9z^2-6xz+x^2]
\\\\=
4y^2-9z^2+6xz-x^2
.\end{array}
