2/3x-1/6y
=2/3 (根号3+根号2)-1/6(根号3-根号2)
=2/3根号3+2/3根号2-1/6根号3+1/6根号2
=(2/3-1/6)根号3+(2/3+1/6)根号2
=1/2根号3+5/6根号2