Question

Factorize the following expression: $-16z+20z^3$

Answer 1

• Factors of $16z$ = $2^2\times 2^2\times z$ …[1]
• Factors of $20z^3$ $=$$2^2\times 5\times z\times z^2$ …[2]
• By comparing [1] and [2], we can say the common factor of $16z$ and $20z^3$ is $2^2\times z$ i.e. $4z$

$\therefore -16z+20z^3=4z\left(-4+5z^2\right)$

Hence, $\mathbf{-}\mathbf{16}\mathit{z}\mathbf{+}\mathbf{20}{\mathit{z}}^{\mathbf{3}}\mathbf{}\mathbf{=}\mathbf{}\mathbf{4}\mathit{z}\left(-4+5z^2\right)$