4
=[(3-2√15+5+3+2√15+5)/(3-5)]^-2=[16/(-2)]^-2=(-8)^-2=1/64
6
=(√17-2)²-(2+√17)²=(√17-2-2-√17)(√17-2+2+√17)=-4*2√17=-8√17
8
1)[7/(3-√2)]²=49/(9-6√2+2)=49/(11-6√2)=49*(11+6√2)/(11-6√2)(11+6√2)=
=49*(11+6√2)/(121-72)=49*(11+6√2)/49=11+6√2
2)[(3-4√3)/(4-√3)]²=(9-24√3+48)/(16-8√3+3)=(57-24√3)/(19-8√3)=
=3(19-8√3)/(19-√3)=3
3)11+6√2-3=8+6√2
9
1)(√5+√3)/(√5-√3)-(√5-√3)/(√5+√3)=(5+2√15+3-5+2√15-3)/(5-3)=
=4√15/2=2√15
2)(√5+√3)/(√5-√3)+(√5-√3)/(√5+√3)=(5+2√15+3+5-2√15+3)/(5-3)=
16/2=8
3)2√15:8=√15/4
4)15/[(√5+√3)²+(√5-√3)²=15/(5+2√15+3+5-2√15+3)=15/16
5)√15/4:15/16=√15/4*16/15=4/√15