Question

Factorise: $x^4-y^4$

Answer 1

We need to factorise $x^4-y^4$

The given expression can be factorised by using property $(a^2-b^2)=(a+b)(a-b)$

It can be written as $x^4-y^4=(x^2{)}^2-(y^2{)}^2$

Here $a=x^2,b=y^2$

Hence, $(x^4-y^4)=(x^2+y^2)(x^2-y^2)=(x^2+y^2)(x+y)(x-y)$