Factorize the following expression.

$a^4-b^4$

Factorize the following expression.

$x^4-{\left(x-z\right)}^4$

Factorize the following expression.

$a^4-2a^2{b}^2+b^4$

Factorize the following expression.

$p^2+6p-16$

Factorized form of $23xy-46x+54y-108$ is:

Simplify the following.

${\left(1.5p+1.2q\right)}^2-{\left(1.5p-1.2q\right)}^2$

Simplify the following.

$\left(x^2-4\right)\left(x^2+4\right)+16$