Factorise fully 3y^(3) -12y

Question

Factorise fully
`3y^(3) -12y`

Answer 1

`{3y}^(3) - 12y \\ = 3y( {y}^(2) - 4) \\ = 3y( {y}^(2) - {2}^(2) ) \\ = 3y(y - 2)(y + 2) \\ = 3y(y + 2)(y - 2)`

Answer 2

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

a=y b=2

3y(y+2)(y-2)