\(\left(x-2\right)\left(x+2\right)\left(x^2-10\right)-72\)
\(=\left(x^2-4\right)\left(x^2-10\right)-72\)
\(=x^4-10x^2-4x^2+40-72\)
\(=x^4-14x^2-32\)
\(=x^4-16x^2+2x^2-32\)
\(=\left(x^4-16x^2\right)+\left(2x^2-32\right)\)
\(=x^2\left(x^2-16\right)+2\left(x^2-16\right)\)
\(=\left(x^2+2\right)\left(x^2-16\right)\)
\(=\left(x^2+2\right)\left(x-4\right)\left(x+4\right)\)