Question

Очень важно!!! Помогите плиз

Answer 1

Ответ:

$1) frac{a - 4}{sqrt a - 2} = frac{(sqrt{a}-2)(sqrt{a} +2)}{sqrt a - 2} = sqrt a + 2\\2) frac{sqrt{23}-23}{sqrt{23}} = frac{(sqrt{23}-23)cdot sqrt{23}}{23} = frac{23-23sqrt{23}}{23} = 1 - sqrt{23}\\3) frac{a-5}{a+2sqrt{5a}+5} = frac{(sqrt{a}-sqrt{5})(sqrt{a}+sqrt{5})}{(sqrt{a}+sqrt{5})(sqrt{a}+sqrt{5})}}} = frac{sqrt{a}-sqrt{5}}{sqrt{a}+sqrt{5}}$