Question

81a⁴-1 factorise it​

Answer 1

Step-by-step explanation:

81a^4

=(9a^2)^2-(1)^2

=(9a^2+1) (9a^2-1)

=(9a^2+1) (9a)^2-(1)^2

=(9a^2+1) (9a+1) (9a-1)

hope its help.Thanks.

Answer 2

Answer:

$81 {a}^{4} - 1 \\ \\ =( {9a ^{2}) }^{2} - {1}^{2} \\ \\ using \: formula \\ \\ {a}^{2} - {b}^{2} \\ \\ = (a + b)(a - b) \\ \\ (9 {a}^{2} + 1)(9 {a}^{2} - 1)$

❥ hope this much helps uh ❣️