√12-√18-√0.5+√1/3
=2√3-3√2-√2/2+√3/3
=2√3+√3/3-(3√2+√2/2)
=7√3/3-7√2/2
﹙√5-2﹚²+﹙√5-3﹚﹙√5+3﹚
=5-4√5+4+5-9
=5-4√5