Срочно! Решить задания по алгебре

$80) \ \ \ \cfrac{ \sqrt{0.08}* \sqrt{0.3} }{ \sqrt{0.0015} }= \sqrt{ \cfrac{0.08*0.3}{0.0015} } = \sqrt{ \cfrac{0.08}{0.005} } = \sqrt{16}=4 \\\\ \\ \\ 60) \ \ \left( \sqrt{16 \cfrac{9}{10}}+ \sqrt{19 \cfrac{6}{10} \right): \cfrac{1}{ \sqrt{250} } =\left( \sqrt{\cfrac{169}{10}}} + \sqrt{\cfrac{196}{10} \right)* \cfrac{ \sqrt{250} }{ 1} =\\\\\\=\left( {\cfrac{13}{ \sqrt{10} }}} + {\cfrac{14}{ \sqrt{10} } \right)* \sqrt{250} = \cfrac{27* \sqrt{25}* \sqrt{10} }{ \sqrt{10} }=27*5=135$

$91) \ \ \sqrt{x^2-4x+4}+ \sqrt{x^2-8x+16}= \sqrt{(x-2)^2}+ \sqrt{(x-4)^2}= \\= x-2+x-4=2x-6$
при х = √7
$2x - 6=2 \sqrt{7}-6$

$82) \ \ 14* \sqrt[4]{27}* \sqrt[12]{27}= 14* \sqrt[4]{3^3}* \sqrt[12]{3^3}=14*3^{ \frac{3}{4} }*3^{ \frac{3}{12} }=\\=14*3^{ \frac{3}{4} }*3^{ \frac{1}{4} }=14*3=42$

$66) \ \ \sqrt{2}* \sqrt{15- \sqrt{7} }* \sqrt{15+ \sqrt{7} } * \sqrt{109}= \\ = \sqrt{2}* \sqrt{(15- \sqrt{7})( 15+ \sqrt{7} )} * \sqrt{109}=\\=\sqrt{2}* \sqrt{225-7 } * \sqrt{109}=\sqrt{2}* \sqrt{218} * \sqrt{109}=\\= \sqrt{2}* \sqrt{2}* \sqrt{109}* \sqrt{109}=2*109 =218$

$102) \ \ \sqrt{21-12 \sqrt{3} }* \sqrt{21+12 \sqrt{3} }= \sqrt{(21-12 \sqrt{3})(21+12 \sqrt{3}) }=\\= \sqrt{441-144*3}= \sqrt{441-432}= \sqrt{9}=3$