2/3.|x|-1/2=2,2
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Ta có:
A = \(\frac{1x^3-3x+\left(x^2-1\right)\sqrt{x^2-4}-2}{x^3-3x+\left(x^2-1\right)\sqrt{x^2-4}-2}\)
= \(\frac{\left(x-2\right)\left(x+1\right)^2+\left(x^2-1\right)\sqrt{x^2-4}}{\left(x+2\right)\left(x-1\right)^2+\left(x^2-1\right)\sqrt{x^2-4}}\)
= \(\frac{\sqrt{x-2}\left(x+1\right)\left(\sqrt{x-2}\left(x+1\right)+\sqrt{x+2}\left(x-1\right)\right)}{\sqrt{x+2}\left(x-1\right)\left(\sqrt{x-2}\left(x+1\right)+\sqrt{x+2}\left(x-1\right)\right)}\)
= \(\frac{\sqrt{x-2}\left(x+1\right)}{\sqrt{x+2}\left(x-1\right)}\)
a: =>x:2,2=15,2x2=30,4
=>x=66,88
b: =>(15/4x+3/4)=-2/3
=>15/4x=-17/12
hay x=-17/45
\(x\times3+x\times2=7,8+2,2\)
\(x\times\left(3+2\right)=10\)
\(x\times5=10\)
\(x=10:5\)
\(x=2\)
Vậy: x = 2
a. 3(2,2−0,3x)=2,6+(0,1x−4)3(2,2−0,3x)=2,6+(0,1x−4)
⇔6,6−0,9x=2,6+0,1x−4⇔6,6−2,6+4=0,1x+0,9x⇔x=8⇔6,6−0,9x=2,6+0,1x−4⇔6,6−2,6+4=0,1x+0,9x⇔x=8
Phương trình có nghiệm x = 8.
b. 3,6−0,5(2x+1)=x−0,25(2−4x)3,6−0,5(2x+1)=x−0,25(2−4x)
⇔3,6−x−0,5=x−0,5+x⇔3,6−0,5+0,5=x+x+x⇔3,6=3x⇔x=1,2⇔3,6−x−0,5=x−0,5+x⇔3,6−0,5+0,5=x+x+x⇔3,6=3x⇔x=1,2
Phương trình có nghiệm x = 1,2
\(x-1\frac{1}{2}=1\frac{1}{3}\)
\(x=1\frac{1}{3}+1\frac{1}{2}\)
\(x=\frac{17}{6}\)
\(x-2,1=2,2\)
\(x=2,2+2,1\)
\(x=4,3\)
1/
a, \(A=\dfrac{2}{3}+\dfrac{3}{4}.\left(-\dfrac{4}{9}\right)=\dfrac{2}{3}-\dfrac{1}{3}=\dfrac{1}{3}\)
b, \(B=2\dfrac{3}{11}.\dfrac{11}{12}.\left(-2,2\right)=\dfrac{25}{11}.\dfrac{11}{12}.\left(-\dfrac{11}{5}\right)=-\dfrac{55}{12}\)
c, \(C=\left(\dfrac{3}{4}-0,2\right):\left(0,4-\dfrac{4}{5}\right)=\left(\dfrac{3}{4}-\dfrac{1}{5}\right):\left(\dfrac{2}{5}-\dfrac{4}{5}\right)=\dfrac{11}{20}:\left(-\dfrac{2}{5}\right)=-\dfrac{11}{8}\)
2/
a, \(\dfrac{11}{12}-x=\dfrac{2}{3}+\dfrac{1}{4}\\ \Rightarrow\dfrac{11}{12}-x=\dfrac{11}{12}\\ \Rightarrow x=0\)
b, \(2x\left(x-\dfrac{1}{7}\right)=0\\ \Leftrightarrow\left\{{}\begin{matrix}2x=0\\x-\dfrac{1}{7}=0\end{matrix}\right.\\ \Leftrightarrow\left\{{}\begin{matrix}x=0\\x=\dfrac{1}{7}\end{matrix}\right.\)
c, \(\dfrac{3}{4}+\dfrac{1}{4}:x=\dfrac{2}{5}\\ \Rightarrow\dfrac{1}{4}:x=-\dfrac{7}{20}\\ \Rightarrow x=-\dfrac{5}{7}\)
\(\frac{2}{3}\left|x\right|-\frac{1}{2}=2,2\)
\(\frac{2}{3}\left|x\right|=\frac{11}{5}+\frac{1}{2}\)
\(\frac{2}{3}\left|x\right|=\frac{22}{10}+\frac{5}{10}\)
\(\frac{2}{3}\left|x\right|=\frac{27}{10}\)
\(\left|x\right|=\frac{27}{10}:\frac{2}{3}\)
\(\left|x\right|=\frac{81}{20}\)
\(\orbr{\begin{cases}x=\frac{81}{20}\\x=-\frac{81}{20}\end{cases}}\)
Vậy x= 81/20 hoặc x= -81/20