Answer:
[tex] {x}^{2} + 9 \\ \\ = {x}^{2} + 3 {}^{2} \\ \\ = (x + 3)(x - 3)[/tex]
[tex] {x}^{2} + 9 = 0[/tex]
[tex] {x}^{2} + 9[/tex]
[tex] {x}^{2} + {3}^{2} [/tex]
[tex](x + 3)(x + 3)[/tex]
