Answer
$9x^4+12x^3-2x^2-4x+1$
Work Step by Step
Using $(a+b+c)^2=a^2+b^2+c^2+2ab+2ac+2bc$ or the square of a multinomial, the product of the given expression, $
(3x^2+2x-1)^2
$, is
\begin{array}{l}
(3x^2)^2+(2x)^2+(-1)^2+2(3x^2)(2x)+2(3x^2)(-1)+2(2x)(-1)
\\\\=
9x^4+4x^2+1+12x^3-6x^2-4x
\\\\=
9x^4+12x^3+(4x^2-6x^2)-4x+1
\\\\=
9x^4+12x^3-2x^2-4x+1
.\end{array}
