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# How do you factor x^2 + 9 ?

Jun 28, 2015

${x}^{2} + 9$ has no (Real) factors (Unlike ${x}^{2} - 9$)

#### Explanation:

The most you could do with this is use the quadratic formula on
$\textcolor{w h i t e}{\text{XXXX}}$${x}^{2} + 0 \cdot x + 9$
to get
$\textcolor{w h i t e}{\text{XXXX}}$$\pm 3 i$

So you could factor using Complex values:
$\textcolor{w h i t e}{\text{XXXX}}$${x}^{2} + 9 = \left(x + 3 i\right) \left(x - 3 i\right)$