\(\left(x^2+4\right)\left(x+2\right)\left(x-2\right)\left(x^2+3\right)\left(x^2-3\right)\)
\(=\left(x^2+4\right)\left(x^2-4\right)\left(x^4-9\right)\)
\(=\left(x^4-16\right)\left(x^4-9\right)\)
\(=x^4\left(x^4-16\right)-9\left(x^4-16\right)\)
\(=x^8-16x^4-9x^4+144\)????