√75-√5-10√5分之1
=5√3-√5+10√5/5
=5√3-√5+2√5
=5√3+√5
√3分之2-4√216+42√6分之1=
=√6/3-4*6√6+42*√6/6
=√6/3-24√6+7√6
=(1/3-24+7)√6
=-50√6/3