Question

Помогите пожалуйста решить номер 8

Answer 1

1) $frac{ sqrt{c} -7 sqrt{d} }{ sqrt{cd}-d } - frac{7 sqrt{c}+ sqrt{d} }{ sqrt{cd}- c }= frac{ sqrt{c}-7 sqrt{d} }{ sqrt{d}( sqrt{c}- sqrt{d} ) }- frac{7 sqrt{c}+ sqrt{d} }{ sqrt{c}( sqrt{d} - sqrt{c} ) }= frac{ sqrt{c} -7 sqrt{d} }{ sqrt{d}( sqrt{c} - sqrt{d}) } + frac{7 sqrt{c} + sqrt{d} }{ sqrt{c}( sqrt{c} - sqrt{d}) }$$= frac{ sqrt{c} * sqrt{c} -7 sqrt{d}* sqrt{c} +7 sqrt{c} * sqrt{d} + sqrt{d} * sqrt{d} }{ sqrt{cd} ( sqrt{c} - sqrt{d} )} =frac{c+d}{ sqrt{cd}( sqrt{c} - sqrt{d} ) }$
2) $frac{c+d}{ sqrt{cd}( sqrt{c} - sqrt{d}) } : frac{c+d}{ sqrt{c}- sqrt{d} }= frac{c+d}{ sqrt{cd}( sqrt{c}- sqrt{d} } * frac{ sqrt{c} - sqrt{d} }{c+d}= frac{1}{ sqrt{cd} }$