Question

[nguyet nguyen]

Tính

\(\dfrac{1}{x-y}\cdot\sqrt{x^4\left(x-y\right)^2}\) (x>y)

\(\sqrt{27}\cdot\sqrt{48\cdot\left(2-a\right)^2}\) (a>2)

\(\left(\sqrt{2012}+\sqrt{2011}\right)\cdot\left(\sqrt{2012}+\sqrt{2011}\right)\)

\(\sqrt{\dfrac{64x^2}{49\left(y+1\right)^2}}\) (x<0;y>-1)

\(\sqrt{\dfrac{121x^2}{144\left(y+2\right)}}\left(x>0;y< -2\right)\)

\(\sqrt{\dfrac{676x^3}{169xy^2}}\left(x>0;y< 1\right)\)

Answer 1

[Nguyễn Lê Phước Thịnh]

a: \(=\dfrac{1}{x-y}\cdot x^2\cdot\left(x-y\right)=x^2\)

b: \(=\sqrt{27\cdot48}\cdot\left|a-2\right|=36\left(a-2\right)\)

c: \(=\left(\sqrt{2012}+\sqrt{2011}\right)^2\)

d: \(=\dfrac{8}{7}\cdot\dfrac{-x}{y+1}\)

e: \(=\dfrac{11}{12}\cdot\dfrac{x}{-y-2}=\dfrac{-11x}{12\left(y+2\right)}\)