a4 – 81 = …………..A) (a – 3) (a + 3) (a2 + 9) B) (a – 3)

1.	a4 – 81 = …………..A) (a – 3) (a + 3) (a2 + 9) B) (a – 3)2 (a2 + 1) C) (a – 3)4 (a + 1) D) None
Answer» A) (a – 3) (a + 3) (a² + 9) Correct option is (A) (a – 3) (a + 3) (a² + 9) \(a^4-81=(a^2)^2-9^2\) \(=(a^2-9)(a^2+9)\) \(=(a^2-3^2)(a^2+9)\) = \((a–3)(a+3)(a^2+9)\)

a4 – 81 = …………..A) (a – 3) (a + 3) (a2 + 9) B) (a – 3)2 (a2 + 1) C) (a – 3)4 (a + 1) D) None

Answer»

A) (a – 3) (a + 3) (a² + 9)

Correct option is (A) (a – 3) (a + 3) (a² + 9)

\(a^4-81=(a^2)^2-9^2\) \(=(a^2-9)(a^2+9)\)

\(=(a^2-3^2)(a^2+9)\)

= \((a–3)(a+3)(a^2+9)\)