Question

Factorise the following:

80y³ – 5y

Answer 1

The given expression is,

80y³ – 5y

= 5y(16y² – 1)

Here we use the identity

a² – b² = (a + b) (a – b)

Taking a = 4y and b = 1, we get

∴ 80y³ – 5y

= 5y((4y)² – (1)²)

= 5y(4y – 1)(4y + 1)

Therefore, the factors of the given expression are 5y(4y – 1) (4y + 1)