\(\left(x-2\right)\left(x^2+4x+4\right)-x\left(x-1\right)\left(x+1\right)+3x=2\)

\(\Leftrightarrow\left(x-2\right)\left(x+2\right)^2-x\left(x^2-1\right)+3x=2\)

\(\Leftrightarrow\left(x^2-4\right)\left(x+2\right)-x^3+x+3x=2\)

\(\Leftrightarrow x^3+2x^2-4x-8-x^3+4x=2\)

\(\Leftrightarrow2x^2=10\)

\(\Leftrightarrow x^2=5\)

\(\Leftrightarrow x=\sqrt{5};x=-\sqrt{5}\)