﹙√5+1﹚﹙√5-1﹚
=(√5)²-1²
=5-1
=4
﹙2-√7﹚﹙2+√7﹚
=2²-(√7)²
=4-7
=-3
﹙2√3+1﹚²
=(2√3)²+4√3+1
=12+4√3+1
=13+4√3
√3-√2/√3+√2
=(√3-√2)²/[(√3+√2)(√3-√2)]
=(3-2√6+2)²/[(√3)²-(√2)²]
=5-2√6
﹙√5+1﹚﹙√5-1﹚
=(√5)²-1²
=5-1
=4
﹙2-√7﹚﹙2+√7﹚
=2²-(√7)²
=4-7
=-3
﹙2√3+1﹚²
=(2√3)²+4√3+1
=12+4√3+1
=13+4√3
√3-√2/√3+√2
=(√3-√2)²/[(√3+√2)(√3-√2)]
=(3-2√6+2)²/[(√3)²-(√2)²]
=5-2√6