Question

Factorise:
$250y^3-\frac{16}{y^3}$

Answer 1

$250y^3-\frac{16}{y^3}$

$=2(125y^3-\frac{8}{y^3})$

$=2({\left(5y\right)}^3-{\left(\frac{2}{y}\right)}^3)$

$=2(5y-\frac{2}{y})(25y^2+5y\times \frac{2}{y}+\frac{4}{y^2})$

$=2(5y-\frac{2}{y})(25y^2+10+\frac{4}{y^2})$

$=2(5y-\frac{2}{y})(25y^2+\frac{4}{y^2}+10)$