Question

Đề : Trục căn thức ở mẫu
a) \(\dfrac{5}{\sqrt{10}}\)                  b) \(\dfrac{5}{2\sqrt{5}}\)              c) \(\dfrac{1}{3\sqrt{20}}\)

d) \(\dfrac{2\sqrt{2}+2}{5\sqrt{2}}\)            e) \(\dfrac{y+b\sqrt{y}}{b\sqrt{y}}\) (với \(b\ge0\) và\(b\ne0\) )

Answer 1

a: \(\dfrac{5}{\sqrt{10}}=\dfrac{5\sqrt{10}}{10}=\dfrac{\sqrt{10}}{2}\)

b: \(\dfrac{5}{2\sqrt{5}}=\dfrac{\sqrt{5}}{2}\)

c: \(\dfrac{1}{3\sqrt{20}}=\dfrac{\sqrt{5}}{30}\)

Answer 2

a)\(\dfrac{5}{\sqrt{10}}=\dfrac{5\sqrt{10}}{10}=\dfrac{\sqrt{10}}{2}\)

b)\(\dfrac{5}{2\sqrt{5}}=\dfrac{5\sqrt{5}}{2.5}=\dfrac{\sqrt{5}}{2}\)

c)\(\dfrac{1}{3\sqrt{20}}=\dfrac{\sqrt{20}}{3.20}=\dfrac{\sqrt{20}}{60}=\dfrac{\sqrt{5}}{30}\)

Answer 3

d)\(\dfrac{2\sqrt{2}+2}{5\sqrt{2}}=\dfrac{2.2+2\sqrt{2}}{5.2}=\dfrac{2+\sqrt{2}}{5}\)

e)\(\dfrac{y+b\sqrt{y}}{b\sqrt{y}}=\dfrac{y\sqrt{y}+by}{by}=\dfrac{\sqrt{y}+b}{b}\)