\(\dfrac{\sqrt{45ab^2}}{\sqrt{20a}}=\sqrt{\dfrac{45ab^2}{20a}}=\sqrt{\dfrac{9}{4}b^2}=\dfrac{3}{2}b\)
\(\dfrac{\sqrt{45ab^2}}{\sqrt{20a}}=\sqrt{\dfrac{45ab^2}{20a}}=\sqrt{\dfrac{9b^2}{4}}=\dfrac{3b}{2}\)
a)\(\sqrt{4\left(a-3\right)^2}vớia\ge3\)
b)\(\sqrt{a^2\left(a+1\right)^2}vớia>0\)
c)\(\sqrt{\dfrac{16a^4b^6}{128a^6b^6}}vớia< 0,b\ne0\)
\(\dfrac{\sqrt{16a^4b^6}}{\sqrt{128a^6b^6}}vớia< 0,b\ne0\)
Câu 48* : Với a
0 thì -2a\(b^2\sqrt{5}\)bằng :
A. \(\sqrt{20a^2b^4}\) ; B. -\(\sqrt{20a^2b^4}\); C. \(\sqrt{10a^2b^4}\) ; D. -\(\sqrt{10a^2b^4}\) .
CM: \(\sqrt{a+b}+\sqrt{a-b}< 2\sqrt{a},vớia,b,c>0\)
Rút gọn biểu thức:
\(\sqrt{\frac{2a}{3}}.\sqrt{\frac{3a}{8}}vớia\ge0\)\(\sqrt{5a}.\sqrt{45a}-3avớia\ge0\)\(4\sqrt{16a^6}-6a^3\rightarrow kq2TH\)\(\left(3-a\right)^2-\sqrt{0,2}.\sqrt{180a^4}\)\(\sqrt{\frac{27.\left(a-3\right)^2}{48}}vớia< 3\)\(\frac{\sqrt{63y^3}}{\sqrt{7y}}vớiy>0\)\(\frac{\sqrt{16a^4b^6}}{\sqrt{128a^6b^2}}vớia< 0,b\ne0\)\(\frac{a-b}{\sqrt{a}-\sqrt{b}}-\frac{\sqrt{a^3}+\sqrt{b^3}}{a-b}\left(a\ge0;b\ge0;a\ne b\right)\)\(\frac{2a+\sqrt{ab}-3b}{2a-5\sqrt{ab}+3b}\left(a,b\ge0;4a\ne9b\right)\)Rút gon các bt sau
A=\(\sqrt{12}\)+2\(\sqrt{27}\)-3\(\sqrt{48}\)
C=\(\sqrt{20a}\)+4\(\sqrt{45a}\)-2\(\sqrt{125a}\)với a≥0
\(\dfrac{a-4\sqrt{a}+4}{\sqrt{a}-2}vớia\ge0,a\ne4\)........Rút gọn
Rút gọn các biểu thức sau:
a) A=\(\dfrac{x\sqrt{y}+y\sqrt{x}}{x+2\sqrt{xy}+y}\)(x≥0 , y≥0 , xy≠0)
b) B=\(\dfrac{x\sqrt{y}-y\sqrt{x}}{x-2\sqrt{xy}+y}\)(x≥0 , y≥0 , x≠y)
c) C=\(\dfrac{3\sqrt{a}-2a-1}{4a-4\sqrt{a}+1}\)(a≥0 , a≠\(\dfrac{1}{4}\))
d) D=\(\dfrac{a+4\sqrt{a}+4}{\sqrt{a}+2}+\dfrac{4-a}{\sqrt{a}-2}\)(a≥0 , a≠4)
với a > 0, b > 0 thì \(\sqrt{\dfrac{a}{b}}+\dfrac{a}{b}\sqrt{\dfrac{b}{a}}\)bằng:
a) 2
b) \(\dfrac{2\sqrt{ab}}{b}\)
c) \(\sqrt{\dfrac{a}{b}}\)
d) \(\sqrt{\dfrac{2a}{b}}\)
