Question

Factorise:

5x⁴ – 80y⁴

Answer 1

Given expression: 5x⁴ – 80y⁴

⇒ 5(x⁴ – 16y⁴)

⇒ 5[(x²)² – (4y²)²]

We know that,

a² – b² = (a + b) (a – b)

Hence,

⇒ 5(x² + 4y²) (x² – 4y²)

⇒ 5(x² + 4y²) [x² – (2y)²]

⇒ 5(x² + 4y²) (x – 2y) (x + 2y)