Question

Factorise the following​

Answer 1

x⁴ - y⁴ + x² - y²

solution

x⁴ + x² - y⁴ - y²

( x² - y² ) ( x² + y² + 1 )

( x - y ) ( x + y )

( x² + y² + 1 ) ( x - y ) ( x + y )