Question

4.17. Алгебра
1,2 и 3 номер ​

Answer 1

1)

$\frac{5a}{\sqrt{5}+2} =\frac{5a(\sqrt{5}-2)}{(\sqrt{5}+2)(\sqrt{5}-2)} =\frac{5a\sqrt{5} -10a}{5-4} =5a\sqrt{5} -10a$

2)

$\frac{2+\sqrt{a}}{2\sqrt{a}} =\frac{(2+\sqrt{a})\sqrt{a}}{2a} =\frac{2\sqrt{a} +a}{2a}$

3)

$\frac{15c}{2-\sqrt{3}} =\frac{15c(2+\sqrt{3})}{(2+\sqrt{3})(2-\sqrt{3})} =\frac{30c+15c\sqrt{3}}{4-3} =30c+15c\sqrt{3}$