Question

How do you factor completely `4x^2-25`?

Answer 1

`(2x+5)(2x-5)`

Explanation:

Realize that `4x^2-25` is a difference of squares. Differences of squares, such as `a^2-b^2`, can be factored into `(a+b)(a-b)`.

Since `4x^2=(2x)^2` and `25=(5)^2`, we can say that `4x^2-25=color(blue)((2x+5)(2x-5)`.