Question

Daca a = |$\sqrt{3} -2 \sqrt{7}$ | si b = | $\sqrt{3} +2 \sqrt{7}$ |
atunci $\frac{ \sqrt{a*b} }{5} -1$

Answer 1

$\sqrt{3} \ \textless \ 2 \sqrt{7} =\ \textgreater \ | \sqrt{3} -2 \sqrt{7} |=2 \sqrt{7} - \sqrt{3} \\ | \sqrt{3} +2 \sqrt{7} |=2 \sqrt{7}+ \sqrt{3} \\ \frac{ \sqrt{(2 \sqrt{7}- \sqrt{3})(2 \sqrt{7}+ \sqrt{3} ) } }{5} = \frac{ \sqrt{28-3} }{5}=1$
1-1=0
$(a-b)(a+b)= a^{2}- b^{2}$