Answer:
[tex]\sf \bold 9\sqrt{2}[/tex]
Step-by-step explanation:
Step1: Prime fatorize and reduce to simplest form
Step2: Combine like radicals
[tex]\sf 3\sqrt{2} - 2\sqrt{18}+6\sqrt{8}= 3\sqrt{2}- 2\sqrt{3*3*2}+6\sqrt{2*2*2}[/tex]
[tex]\sf = 3\sqrt{2}-2*3\sqrt{2} +6*2\sqrt{2}\\\\=3\sqrt{2}-6\sqrt{2}+12\sqrt{2}\\\\=(3-6+12)\sqrt{2}\\\\ = 9\sqrt{2}[/tex]