Question

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

Answer 1

In the the general form
`(a^2 - b^2) = (a-b)*(a+b)`

This form fits the given expression `(4-25x^2)`
with `a^2=2^2` and `b^2=(5x)^2`

so `(4-25x^2)` can be factored as
`(2-5x)(2+5x)`