bài 2: Thực hiện các phép tính
9) K= \(\dfrac{2\sqrt{7}-\sqrt{14}}{2-\sqrt{2}}-\sqrt{28}+\sqrt{7}-\sqrt{5}\)
10) M= \(\dfrac{3+2\sqrt{3}}{\sqrt{3}}+\dfrac{2+\sqrt{2}}{\sqrt{2}+1}-\left(2+\sqrt{3}\right)\)
11) L= \(\dfrac{2\sqrt{8}-\sqrt{12}}{\sqrt{18}-\sqrt{48}}-\dfrac{\sqrt{5}+\sqrt{27}}{\sqrt{30}+\sqrt{162}}\)
12) G= \(\dfrac{1}{1+\sqrt{5}}+\dfrac{1}{\sqrt{5}+\sqrt{9}}+\dfrac{1}{\sqrt{9}+\sqrt{13}}+....+\dfrac{1}{\sqrt{2001}+\sqrt{2005}}\)
Bài 3: Phân tích đa thức thành nhân tử
1) x - y - 3( \(\sqrt{x}+\sqrt{y}\) )
3) \(x\sqrt{y}-y\sqrt{y}+\sqrt{x^2y}-\sqrt{xy^2}\)
4) \(5x^2-7x\sqrt{y}+2y\)
5) \(\sqrt{1-a}+\sqrt{1-a^2}\)
6) x - y + \(\sqrt{xy^2}-\sqrt{y^3}\)
mn giải chi tiết giúp mk vs ạ! mk đang cần gấp
Bài 3:
1: \(=\left(\sqrt{x}+\sqrt{y}\right)\left(\sqrt{x}-\sqrt{y}\right)-3\left(\sqrt{x}+\sqrt{y}\right)\)
\(=\left(\sqrt{x}+\sqrt{y}\right)\left(\sqrt{x}-\sqrt{y}-3\right)\)
4: \(=5x^2-5x\sqrt{y}-2x\sqrt{y}+2y\)
\(=5x\left(x-\sqrt{y}\right)-2\sqrt{y}\left(x-\sqrt{y}\right)\)
\(=\left(x-\sqrt{y}\right)\left(5x-2\sqrt{y}\right)\)
5: \(=\sqrt{1-a}\left(1+\sqrt{1+a}\right)\)
6: \(=\left(\sqrt{x}-\sqrt{y}\right)\left(\sqrt{x}+\sqrt{y}\right)+y\left(\sqrt{x}-\sqrt{y}\right)\)
\(=\left(\sqrt{x}-\sqrt{y}\right)\left(y+\sqrt{x}+\sqrt{y}\right)\)
