solution
[tex]\begin{gathered} (2\sqrt[]{x}-6)(\sqrt[]{x}-2) \\ 2\sqrt{x}\sqrt{x}+2\sqrt{x}\mleft(-2\mright)+\mleft(-6\mright)\sqrt{x}+\mleft(-6\mright)\mleft(-2\mright) \\ 2\sqrt{x}\sqrt{x}-2\cdot\: 2\sqrt{x}-6\sqrt{x}+6\cdot\: 2 \\ 2x-10\sqrt{x}+12 \end{gathered}[/tex]answer is:
[tex]2x-10\sqrt[]{x}+12[/tex]