Question

How do you factor `x^2 + 9`?

Answer 1

`x^2+9` has no (Real) factors (Unlike `x^2-9`)

Explanation:

The most you could do with this is use the quadratic formula on
`color(white)("XXXX")` `x^2+0*x+9`
to get
`color(white)("XXXX")` `+-3i`

So you could factor using Complex values:
`color(white)("XXXX")` `x^2+9 = (x+3i)(x-3i)`