Question

ajutatima sa rezolv exercitiul

Answer 1

$\frac{2- \sqrt{5} }{2+ \sqrt{5} } = \frac{(2- \sqrt{5} )*(2- \sqrt{5}) }{ 2^{2} - ( \sqrt{5} )^{2} }= \frac{ (2- \sqrt{5} )^{2} }{-1} = \frac{4-4 \sqrt{5}+5 }{-1} = \frac{9-4 \sqrt{5} }{-1}=4 \sqrt{5} -9$