Question

Factorise : x^4 - 1​

Answer 1

Answer:

Rewrite x4 as (x2)2 ( x 2 ) 2 . Rewrite 1 as 12 . Since both terms are perfect squares, factor using the difference of squares formula, a2−b2=(a+b)(a−b) a 2 - b 2 = ( a + b ) ( a - b ) where a=x2 a = x 2 and b=1 .

Answer 2

x⁴-1

=(x²)²-1²

=(x²-1)(x²+1)

=(x²-1²)(x+1)

=(x-1)(x+1)(x²+1)

Formula used:

a²-b²=(a-b)(a+b)