Question

упростить вырожение

Answer 1

$1) sqrt{2}( sqrt{18} +4 sqrt{2} )= sqrt{2}( 3sqrt{2} +4 sqrt{2} )= sqrt{2}*7 sqrt{2}=7*2=14 \ \ 2) frac{ sqrt{12}- sqrt{21} }{ sqrt{3} } =frac{ 2sqrt{3}- sqrt{21} }{ sqrt{3} }=frac{ (2sqrt{3}- sqrt{21}) sqrt{3} }{3 }= frac{6- sqrt{63} }{3}= frac{6-3 sqrt{7} }{3}= frac{3(2- sqrt{7} )}{3}= \ =2- sqrt{7}$

$3)(2 sqrt{5}- sqrt{2} )( sqrt{15}-5 sqrt{6} )=2 sqrt{75}-10 sqrt{30}- sqrt{30 }+5sqrt{12} = \ = 10sqrt{3} -11 sqrt{30}+10 sqrt{3}=20 sqrt{3}-11 sqrt{30}$