Question

How do you factor `16 - 9y^2`?

Answer 1

`16-9y^2=color(green)((4-3y)(4+3y))`

Explanation:

Remember in general that
`color(white)("XXX")(a^2-b^2)=(a-b)(a+b)`

`16-9y` can be written as
`color(white)("XXX")(4)^2-(3y)^2`

Using `4=a` and `(3y)=b` in the general equation
we see that the original expression can be factored as
`color(white)("XXX")(4-3y)(4+3y)`