Question

Simplify: (a + 1) (a – 1) (a2 + 1)

Answer 1

Answer:

The answer is $a^4-1$

Step-by-step explanation:

$(a+1)(a-1)(a^2+1)$

Using $(a+b)(a-b)=a^2-b^2$

$=(a^2-1^2)(a^2+1)\\=(a^2-1)(a^2+1)$

Again use above results

$=(a^2)^2-1^2\\=a^4-1$

Answer 2

Step-by-step explanation:

$(a + 1)(a - 1)( {a}^{2} + 1)$

$= ( {a}^{2} - 1)( {a}^{2} + 1)$

$= ( { {a}^{2} })^{2} - ( {1}^{2} )$

$= ( {a}^{4} - 1)$