Question

How do you multiply `(5x-1)(5x+1)`?

Answer 1

`25x^2-1`
This is a difference of squares where:
`(a^2-b^2) = (a+b)(a-b)`

If we let `a=5x` and `b=1`
`((5x)^2-(1)^2) = (5x+1)(5x-1)`