Solve for: 8z^8-18

Expression: $8{z}^{8}-18$

Factor out $2$ from the expression

$2\left( 4{z}^{8}-9 \right)$

Use ${a}^{2}-{b}^{2}=\left( a-b \right)\left( a+b \right)$ to factor the expression

$2\left( 2{z}^{4}-3 \right) \times \left( 2{z}^{4}+3 \right)$