Answer :
[tex]2\sqrt2+\sqrt{18}+\sqrt8=2\sqrt2+\sqrt{9\cdot2}+\sqrt{4\cdot2}\\\\=2\sqrt2+\sqrt9\cdot\sqrt2+\sqrt4\cdot\sqrt2=2\sqrt2+3\sqrt2+2\sqrt2=7\sqrt2\\\\Answer:A.\ 7\sqrt2[/tex]
[tex] \sqrt{18} = \sqrt{3*3*2} = 3\sqrt{2} \\ \sqrt{8} = \sqrt{2*2*2} =2 \sqrt{2}
\\ 2 \sqrt{2} + 3 \sqrt{2} + 2\sqrt{2} = 7 \sqrt{2} [/tex]
\\ 2 \sqrt{2} + 3 \sqrt{2} + 2\sqrt{2} = 7 \sqrt{2} [/tex]