Answer:
[tex](x+3\sqrt{2})(x-3\sqrt{2})[/tex]
Step-by-step explanation:
The given expression is [tex]x^2-18[/tex].
The technique that can be used to factor this polynomial is the difference of two squares.
We rewrite the two expressions as;
[tex]x^2-(\sqrt{18})^2[/tex]
Recall that;
[tex]a^2-b^2=(a+b)(a-b)[/tex]
[tex]x^2-(\sqrt{18})^2=(x+\sqrt{18})(x-\sqrt{18})[/tex]
[tex]x^2-(\sqrt{18})^2=(x+3\sqrt{2})(x-3\sqrt{2})[/tex]
