Question

factor 9x^2+25 ???

Answer 1

This does not factor over \(\mathbb{R}\).

Have you made a typo?

Answer 2

oh yeah sorry its supposed to be 9x^2-25

Answer 3

Use this:
\[(a+b)(a-b)=a^2-b^2\]

Answer 4

9 is a and -25 is b right?

Answer 5

Not quite. \(a^2=9x^2\), so you take the square root of both sides: \(a=\pm \sqrt{9x^2}=\pm 3x\). Take the positive for cosmetic reasons, and repeat this process for \(b^2=25\).