We have [tex]2x^2-8[/tex].
First let us factor the 2 to obtain,
[tex]2(x^2-4)[/tex]
We can now see clearly that the expression inside the parentheses is a difference of two squares.
We now write the 4 as 2². So that we obtain the expression,
[tex]2(x^2-2^2)[/tex]
Recall that
[tex]a^2-b^2=(a+b)(a-b)[/tex]
Hence our expression becomes,
[tex]2(x+2)(x-2)[/tex]
Therefore, when factored completely,
[tex]2x^2-8=2(x+2)(x-2)[/tex]
