原式=（1/3*3√3-2√ 6+3*√6/3）*3√2 =（√3-2√6+√6）*3√2 =（√3-√6）*3√2 =3√6-6√3
(1/3√27-√24+3√2/3)*√18=(√3-2√6+√6)*3√2=(√3-√6)*3√2=3√6-6√3
3根号6减6根号3
