Question

How do you multiply `(4x-1)(4x+1)`?

Answer 1

`16x^2-1`

Explanation:

let `4x=a` and `1=b`
`(a+b)(a-b)=a^2-ab+ab-b^2`
`=a^2-b^2`
substitute back the values
`(4x)^2-(1)^2`=`16x^2-1`