Question

$frac{ sqrt 35- sqrt{7} }{ sqrt5-5}$*$sqrt{45}$

Answer 1

умножаем на (sqrt5+5)/(sqrt5+5)

тогда ((5sqrt7-sqrt35-5sqrt35-5sqrt7)*3sqrt5) / (5-25) = 9sqrt(5*35) /10 = 45sqrt7/10 = (9sqrt7) / 2