Làm tính chia:
a,(\(3\sqrt{x^2y}\)-\(4\sqrt{xy^2}\)+5xy):\(\sqrt{xy}\)
b,(\(\sqrt{a^3b}\)+\(\sqrt{ab}\)-\(3\sqrt{ab^3}\)):\(\sqrt{ab}\)
1. làm tính nhân :
a)\(\left(\sqrt{12}-3\sqrt{75}\right).\sqrt{3}\)
b) \(\left(\sqrt{18}-4\sqrt{72}\right).2\sqrt{2}\)
c) \(\left(\sqrt{6}-2\right)\left(\sqrt{6}+7\right)\)
d) \(\left(\sqrt{3}+2\right)\left(\sqrt{3}-5\right)\)
2) thực hien phep tinh :
a) \(\left(\sqrt{48}-\sqrt{27}+4\sqrt{12}\right):\sqrt{3}\)
b) \(\left(\sqrt{20}-3\sqrt{45}+6\sqrt{180}\right):\sqrt{5}\)
c) \(\left(2\sqrt{20}-3\sqrt{45}+4\sqrt{80}\right):\sqrt{5}\)
d) \(\left(3\sqrt{24}+4\sqrt{54}-5\sqrt{96}\right):\sqrt{6}\)
e)\(\left(\sqrt{x^2y}-\sqrt{xy^2}\right):\sqrt{xy}\)
f) \(\left(\sqrt{a^3b}+\sqrt{ab^3}-ab\right):\sqrt{ab}\)
g) \(\left(3\sqrt{x^2y}-4\sqrt{xy^2}+5xy\right):\sqrt{xy}\)
h) \(\left(\sqrt{a^3b}+\sqrt{ab^3-3\sqrt{ab}}\right):\sqrt{ab}\)
1.a) (\(\sqrt{12}\) -3\(\sqrt{75}\))\(\sqrt{3}\)
=\(\sqrt{12}\).\(\sqrt{3}\)-3\(\sqrt{75}\).\(\sqrt{3}\)
=\(2\sqrt{3}.\sqrt{3}-3.5\sqrt{3}.\sqrt{3}\)
=2.3-15.3
=6-45
= -39
b)\(\left(\sqrt{18}-4\sqrt{72}\right)2\sqrt{2}\)
\(\left(3\sqrt{2}-4.6\sqrt{2}\right).2\sqrt{2}\)
\(\left(3\sqrt{2}-24\sqrt{2}\right).2\sqrt{2}\)
\(3\sqrt{2}.2\sqrt{2}-24\sqrt{2}.2\sqrt{2}\)
= 6.2-48.2 = 12-96= -84
d)\(\left(\sqrt{3}+2\right)\left(\sqrt{3}-5\right)\)
\(3-5\sqrt{3}+2\sqrt{3}-10\)
\(-7-3\sqrt{3}\)
\(\)c)\(\left(\sqrt{6}-2\right)\left(\sqrt{6}+7\right)\)
\(\Leftrightarrow6+6\sqrt{7}-2\sqrt{6}-14\)
\(\Leftrightarrow-8+5\sqrt{6}\)
d)\(\left(\sqrt{3}+2\right)\left(\sqrt{3}-5\right)\)
\(\Leftrightarrow3-5\sqrt{3}+2\sqrt{3}-3\)
\(\Leftrightarrow-3\sqrt{3}\)
Bài 2:
a: \(=\dfrac{4\sqrt{3}-3\sqrt{3}+8\sqrt{3}}{\sqrt{3}}=4-3+8=9\)
b: \(=\dfrac{2\sqrt{5}-9\sqrt{5}+36\sqrt{5}}{\sqrt{5}}=2-9+36=29\)
c: \(=\dfrac{4\sqrt{5}-9\sqrt{5}+16\sqrt{5}}{\sqrt{5}}=4-9+16=11\)
d: \(=\dfrac{6\sqrt{6}+12\sqrt{6}-20\sqrt{6}}{\sqrt{6}}=6+12-20=-2\)
e: \(=\sqrt{x}-\sqrt{y}\)
. Làm tính nhân :
a) \(\left(\sqrt{12}-3\sqrt{75}\right).\sqrt{3}\)
b) \(\left(\sqrt{18}-4\sqrt{72}\right).2\sqrt{2}\)
c) \(\left(\sqrt{6}-2\right)\left(\sqrt{6}+7\right)\)
d) \(\left(\sqrt{3}+2\right)\left(\sqrt{3}-5\right)\)
2 . Thực hiện phép tính :
a) \(\left(\sqrt{48}-\sqrt{27}+4\sqrt{12}\right):\sqrt{3}\)
b) \(\left(\sqrt{20}-3\sqrt{45}+6\sqrt{180}\right):\sqrt{5}\)
c) \(\left(2\sqrt{20}-3\sqrt{45}+4\sqrt{80}\right):\sqrt{5}\)
d) \(\left(3\sqrt{24}+4\sqrt{54}-5\sqrt{96}\right):\sqrt{6}\)
e) \(\left(\sqrt{x^2y}-\sqrt{xy^2}\right):\sqrt{xy}\)
f) \(\left(\sqrt{a^3b}+\sqrt{ab^3}-ab\right):\sqrt{ab}\)
g) \(\left(3\sqrt{x^2y}-4\sqrt{xy^2}+5xy\right):\sqrt{xy}\)
h) \(\left(\sqrt{a^3b}+\sqrt{ab^3}-3\sqrt{ab}\right):\sqrt{ab}\)
1. c)\(\left(\sqrt{6}-2\right)\left(\sqrt{6}+7\right)\)
\(\Leftrightarrow6+7\sqrt{6}-2\sqrt{6}-14\)
\(\Leftrightarrow-8+5\sqrt{6}\)
d)\(\left(\sqrt{3}+2\right)\left(\sqrt{3}-5\right)\)
\(\Leftrightarrow3-5\sqrt{3}+2\sqrt{3}-3\)
\(\Leftrightarrow-3\sqrt{3}\)
Bài 2:
a: \(=\dfrac{4\sqrt{3}-3\sqrt{3}+8\sqrt{3}}{\sqrt{3}}=4-3+8=9\)
b: \(=\dfrac{2\sqrt{5}-9\sqrt{5}+36\sqrt{5}}{\sqrt{5}}=2-9+36=29\)
c: \(=\dfrac{4\sqrt{5}-9\sqrt{5}+16\sqrt{5}}{\sqrt{5}}=4-9+16=11\)
d: \(=\dfrac{6\sqrt{6}+12\sqrt{6}-20\sqrt{6}}{\sqrt{6}}=18-20=-2\)
Cho biểu thức:
A = (\(\sqrt{x}\) + \(\dfrac{y-\sqrt{xy}}{\sqrt{x}+\sqrt{y}}\)) : (\(\dfrac{x}{\sqrt{xy}+y}\) + \(\dfrac{y}{\sqrt{xy}-x}\) - \(\dfrac{x+y}{\sqrt{xy}}\))
a) Rút gọn A
b) Tính giá trị của biểu thức A biết x = 3; y = 4 + 2\(\sqrt{3}\)
chứng minh đẳng thức sau :
a. \(\dfrac{a\sqrt{a}+b\sqrt{b}}{\sqrt{a}+\sqrt{b}}-\sqrt{ab}=\left(\sqrt{a}-\sqrt{b}\right)^2\)
b. \(\dfrac{3}{xy}=\dfrac{3x+3z}{x^2y+xyz}\)
\(a,VT=\dfrac{\left(\sqrt{a}+\sqrt{b}\right)\left(a-\sqrt{ab}+b\right)}{\sqrt{a}+\sqrt{b}}-\sqrt{ab}\\ =a-2\sqrt{ab}+b=\left(\sqrt{a}-\sqrt{b}\right)^2=VP\\ b,VP=\dfrac{3\left(x+z\right)}{xy\left(x+z\right)}=\dfrac{3}{xy}=VP\)
1/ \(ab+b\sqrt{a}+\sqrt{a}+1\)
2/ \(\sqrt{x^3}-\sqrt{y^3}+\sqrt{x^2y}-\sqrt{xy^2}\)
3/ \(xy-y\sqrt{x}+\sqrt{x}-1\)
4/\(\sqrt{ax}-\sqrt{by}+\sqrt{bx}-\sqrt{ay}\)
5/ \(\sqrt{a+b}+\sqrt{a^2+b^2}\)
6/\(12-\sqrt{x}-x\)
Rút gọn:
\(A=\dfrac{\sqrt[3]{x^4}+\sqrt[3]{x^2y^2}+\sqrt[3]{y^4}}{\sqrt[3]{x^2}+\sqrt[3]{xy}+\sqrt[3]{y^2}}\)
\(B=\dfrac{\sqrt[3]{xy}\left(\sqrt[3]{y^2}-\sqrt[3]{x^2}\right)+\left(\sqrt[3]{x^4}-\sqrt[3]{y^4}\right)}{\sqrt[3]{x^4}+\sqrt[3]{x^2y^2}-\sqrt[3]{x^3y}}.\sqrt[3]{x^2}\)
\(C=\left(\dfrac{x\sqrt[3]{x}-2x\sqrt[3]{y}+\sqrt[3]{x^2y^2}}{\sqrt[3]{x^2}-\sqrt[3]{xy}}+\dfrac{\sqrt[3]{x^2y}-\sqrt[3]{xy^2}}{\sqrt[3]{x}-\sqrt[3]{y}}\right).\dfrac{1}{\sqrt[3]{x^2}}\)
Tìm điều kiện xác định và phân tích các đa thức sau thành nhân tử:
\(A=\sqrt{xy}-2\sqrt{y}-5\sqrt{x}+10\)
\(B=a\sqrt{x}+b\sqrt{y}-\sqrt{xy}-ab\)
\(C=\sqrt{x^3}-\sqrt{y^3}+\sqrt{x^2y}-\sqrt{xy^2}\)
\(D=\sqrt{x^2+3x+2}+\sqrt{x+1}+2\sqrt{x+2}+2\)
\(A,ĐKXĐ:x;y\ge0\)
\(A=\sqrt{xy}-2\sqrt{y}-5\sqrt{x}+10\)
\(=\sqrt{y}\left(\sqrt{x}-2\right)-5\left(\sqrt{x}-2\right)\)
\(=\left(\sqrt{x}-2\right)\left(\sqrt{y}-5\right)\)
\(ĐKXĐ:x;y\ge0\)
\(B=a\sqrt{x}+b\sqrt{y}-\sqrt{xy}-ab\)
\(=\left(a\sqrt{x}-\sqrt{xy}\right)+\left(b\sqrt{y}-ab\right)\)
\(=\sqrt{x}\left(a-\sqrt{y}\right)+b\left(\sqrt{y}-a\right)\)
\(=\sqrt{x}\left(a-\sqrt{y}\right)-b\left(a-\sqrt{y}\right)\)
\(=\sqrt{x}\left(a-\sqrt{y}\right)-b\left(a-\sqrt{y}\right)\)
\(=\left(a-\sqrt{y}\right)\left(\sqrt{x}-b\right)\)
\(ĐKXĐ:x;y\ge0\)
\(C=\sqrt{x^3}-\sqrt{y^3}+\sqrt{x^2y}-\sqrt{xy^2}\)
\(=\left(\sqrt{x^3}+\sqrt{x^2y}\right)-\left(\sqrt{y^3}+\sqrt{xy^2}\right)\)
\(=\sqrt{x^2}\left(\sqrt{x}+\sqrt{y}\right)-\sqrt{y^2}\left(\sqrt{y}+\sqrt{x}\right)\)
\(=\left(\sqrt{x}+\sqrt{y}\right)\left(x-y\right)\)
\(=\left(\sqrt{x}+\sqrt{y}\right)\left(\sqrt{x}-\sqrt{y}\right)\left(\sqrt{x}+\sqrt{y}\right)\)
\(=\left(\sqrt{x}+\sqrt{y}\right)^2\left(\sqrt{x}-\sqrt{y}\right)\)
Rút gọn
\(A=\left(\sqrt{ab}-\frac{ab}{a+\sqrt{ab}}\right):\frac{\sqrt[4]{ab}-\sqrt{b}}{a-b}\)
\(B=\left(\sqrt{x}+\frac{y-\sqrt{xy}}{\sqrt{x}+\sqrt{y}}\right):\left(\frac{x}{\sqrt{xy}+y}+\frac{y}{\sqrt{xy}+x}-\frac{x+y}{\sqrt{xy}}\right)\)
Rút gọn
\(A=\left(\sqrt{ab}-\frac{ab}{a+\sqrt{ab}}\right):\frac{\sqrt[4]{ab}-\sqrt{b}}{a-b}\)
\(B=\left(\sqrt{x}+\frac{y-\sqrt{xy}}{\sqrt{x}+\sqrt{y}}\right):\left(\frac{x}{\sqrt{xy}+y}+\frac{y}{\sqrt{xy}-y}-\frac{x-y}{\sqrt{xy}}\right)\)