a: \(A=\left(\sqrt{27}-\sqrt{12}+\sqrt{48}\right)\cdot\sqrt{3}\)
\(=\left(3\sqrt{3}-2\sqrt{3}+4\sqrt{3}\right)\cdot\sqrt{3}\)
\(=5\sqrt{3}\cdot\sqrt{3}=15\)
b: \(B=\left(\dfrac{\sqrt{x}}{\sqrt{x}-1}-\dfrac{1}{x-\sqrt{x}}\right):\dfrac{\sqrt{x}+1}{3\sqrt{x}}\)
\(=\left(\dfrac{\sqrt{x}}{\sqrt{x}-1}-\dfrac{1}{\sqrt{x}\left(\sqrt{x}-1\right)}\right)\cdot\dfrac{\left(3\sqrt{x}\right)}{\sqrt{x}+1}\)
\(=\dfrac{x-1}{\sqrt{x}\left(\sqrt{x}-1\right)}\cdot\dfrac{3\sqrt{x}}{\sqrt{x}+1}=3\)
Đúng 1
Bình luận (0)
