Question

30 pontos galera ne ajudem..

Answer 1

$(3 \sqrt{7} + \sqrt{5} )^2~\to~9*7+2*3 \sqrt{7}* \sqrt{5}+5~\to~68+6 \sqrt{35}$

$(3 \sqrt{7} )^2~\to~9*7~\to~63$

$( \sqrt{5} )^2~\to~5$

Agora substitui 


$\frac{(3\sqrt7+ \sqrt{5} )^2-(3 \sqrt{7} )^2-( \sqrt{5} )^2}{ \sqrt{140} }$

$\frac{68+6 \sqrt{35} -63-5}{ 2\sqrt{35 }}\\ \\ \frac{6 \sqrt{35} }{2 \sqrt{35} }$

$\boxed{3}$