Question

Помогите решить 3 и 4 номер по алгебре

Answer 1

3a)$frac{ sqrt{10}+5 }{2+ sqrt{10} } = frac{ sqrt{5*2}+( sqrt{5}) ^{2} }{( sqrt{2}) ^{2}+ sqrt{2*5} } = frac{ sqrt{5}( sqrt{2} + sqrt{5} ) }{ sqrt{2}( sqrt{2} + sqrt5)} }= frac{ sqrt{5} }{ sqrt{2} } = frac{ sqrt{5} * sqrt{2} }{ sqrt{2}* sqrt{2} } = frac{ sqrt{10} }{2}$
б) $frac{x-3 sqrt{x} }{2 sqrt{x} -6} = frac{( sqrt{x} ) ^{2}-3 sqrt{x} }{2( sqrt{x} -3)}= frac{ sqrt{x} ( sqrt{x} -3)}{2( sqrt{x} -3)} = frac{ sqrt{x} }{2}$
4a)$frac{7}{2 sqrt{21} } = frac{7* sqrt{21} }{2 sqrt{21} * sqrt{21} }= frac{7 sqrt{21} }{42} = frac{ sqrt{21} }{6}$
б) $frac{22}{ sqrt{13} - sqrt{2} } = frac{22( sqrt{13}+ sqrt{2} ) }{( sqrt{13}- sqrt{2})( sqrt{13}+ sqrt{2}) } = frac{22( sqrt{13}+ sqrt{2} ) }{13-2}= frac{22( sqrt{13}+ sqrt{2}) }{11} =$$2( sqrt{13} + sqrt{2} )$