Question

(корень45-корень5)^2/20

Answer 1

$\frac{( \sqrt{45} - \sqrt{5})^2 }{20}= \frac{( \sqrt{45})^2+( \sqrt{5})^2-2 \sqrt{45*5} }{20}= \frac{45+5-2 \sqrt{5*9*5} }{20}= \frac{50-2*5*3}{20}=\\\\= \frac{50-30}{20}= \frac{20}{20}=1$