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17 tháng 9 2020

                          Bài làm :

\(a\text{)}...\Leftrightarrow\orbr{\begin{cases}x-3=0\\x-4=0\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=3\\x=4\end{cases}}\)

\(b\text{)}...\Leftrightarrow\orbr{\begin{cases}\frac{1}{2}x-4=0\\x-\frac{1}{4}=0\end{cases}}\Leftrightarrow\orbr{\begin{cases}\frac{1}{2}x=4\\x=0+\frac{1}{4}\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=8\\x=\frac{1}{4}\end{cases}}\)

\(c\text{)}...\Leftrightarrow\orbr{\begin{cases}\frac{1}{3}-x=0\\\frac{1}{2}+1\div x=0\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=\frac{1}{3}-0\\1\div x=-\frac{1}{2}\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=\frac{1}{3}\\x=-2\end{cases}}\)

\(d\text{)}...\Leftrightarrow\left(x+3\right)\left(x-4+2\right)=0\Leftrightarrow\left(x+3\right)\left(x-2\right)=0\Leftrightarrow\orbr{\begin{cases}x+3=0\\x-2=0\end{cases}\Leftrightarrow}\orbr{\begin{cases}x=-3\\x=2\end{cases}}\)

Bài làm :

\(a,\left(x-3\right)\left(x-4\right)=0\)

\(\Rightarrow\orbr{\begin{cases}x-3=0\\x-4=0\end{cases}}\Rightarrow\orbr{\begin{cases}x=3\\x=4\end{cases}}\)

\(b,\left(\frac{1}{2}x-4\right)\left(x-\frac{1}{4}\right)=0\)

\(\Rightarrow\orbr{\begin{cases}\frac{1}{2}x-4=0\\x-\frac{1}{4}=0\end{cases}}\Rightarrow\orbr{\begin{cases}\frac{1}{2}x=4\\x=\frac{1}{4}\end{cases}}\Rightarrow\orbr{\begin{cases}x=8\\x=\frac{1}{4}\end{cases}}\)

\(c,\left(\frac{1}{3}-x\right).\left(\frac{1}{2}+1:x\right)=0\)

\(\Rightarrow\orbr{\begin{cases}\frac{1}{3}-x=0\\\frac{1}{2}+1:x=0\end{cases}}\Rightarrow\orbr{\begin{cases}x=\frac{1}{3}\\x=-2\end{cases}}\)

\(d,\left(x+3\right)\left(x-4\right)+2\left(x+3\right)=0\)

\(\Rightarrow\left(x+3\right)\left(x-4+2\right)=0\)

\(\Rightarrow\left(x+3\right)\left(x-2\right)=0\)

\(\Rightarrow\orbr{\begin{cases}x+3=0\\x-2=0\end{cases}}\Rightarrow\orbr{\begin{cases}x=-3\\x=2\end{cases}}\)

Học tốt nhé

17 tháng 9 2020

a, ( x - 3 ) . ( x - 4 )  = 0              

=> x - 3 = 0 hoặc x - 4 = 0 

Nếu x - 3 = 0 => x = 3 

Nếu x - 4 = 0 => x = 4 

b, (\(\frac{1}{2}\)x  - 4 ) . ( x - \(\frac{1}{4}\)) = 0 

=>(  \(\frac{1}{2}\)x - 4 ) = 0    Hoặc  ( x - \(\frac{1}{4}\)) = 0 

Nếu ( \(\frac{1}{2}\)x - 4 ) = 0  => x = \(\frac{8}{1}\)

Nếu ( x - \(\frac{1}{4}\)) = 0     => x = \(\frac{1}{4}\)

c, (\(\frac{1}{3}\)- x ) . ( \(\frac{1}{2}\)+ 1 : x ) = 0 

=> ( \(\frac{1}{3}\)- x ) = 0 Hoặc ( \(\frac{1}{2}\)+ 1 : x ) = 0

Nếu (\(\frac{1}{3}\)- x ) = 0 => x = \(\frac{1}{3}\)

Nếu ( \(\frac{1}{2}\)+ 1 : x ) = 0 => x = \(\frac{-2}{1}\)

d, ( x + 3 ) . (  x - 4 ) + 2.(x + 3 ) = 0

=> (X + 3 ) = 0 Hoặc  ( x - 4 ) = 0 Hoặc 2. ( x + 3 ) = 0

Nếu x + 3 = 0 => x = 0

Nếu ( x - 4 ) = 0 => x = 4 

Nếu 2.(x + 3) = 0  => x = 3 

# Cụ MAIZ 

17 tháng 9 2020

a. ( x - 3 ) ( x - 4 ) = 0

<=> \(\orbr{\begin{cases}x-3=0\\x-4=0\end{cases}}\)

<=> \(\orbr{\begin{cases}x=3\\x=4\end{cases}}\)

b. \(\left(\frac{1}{2}x-4\right)\left(x-\frac{1}{4}\right)=0\)

<=> \(\orbr{\begin{cases}\frac{1}{2}x-4=0\\x-\frac{1}{4}=0\end{cases}}\)

<=> \(\orbr{\begin{cases}x=8\\x=\frac{1}{4}\end{cases}}\)

17 tháng 9 2020

          Bài làm :

\(a\text{)}...\Leftrightarrow\orbr{\begin{cases}x-3=0\\x-4=0\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=3\\x=4\end{cases}}\)

\(b\text{)}...\Leftrightarrow\orbr{\begin{cases}\frac{1}{2}x-4=0\\x-\frac{1}{4}=0\end{cases}}\Leftrightarrow\orbr{\begin{cases}\frac{1}{2}x=4\\x=0+\frac{1}{4}\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=8\\x=\frac{1}{4}\end{cases}}\)

\(c\text{)}...\Leftrightarrow\orbr{\begin{cases}\frac{1}{3}-x=0\\\frac{1}{2}+1\div x=0\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=\frac{1}{3}-0\\1\div x=-\frac{1}{2}\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=\frac{1}{3}\\x=-2\end{cases}}\)

\(d\text{)}...\Leftrightarrow\left(x+3\right)\left(x-4+2\right)=0\Leftrightarrow\left(x+3\right)\left(x-2\right)=0\Leftrightarrow\orbr{\begin{cases}x+3=0\\x-2=0\end{cases}\Leftrightarrow}\orbr{\begin{cases}x=-3\\x=2\end{cases}}\)

Bài 2: 

a: =>x=0 hoặc x=-3

b: =>x-2=0 hoặc 5-x=0

=>x=2 hoặc x=5

c: =>x-1=0

hay x=1

12 tháng 7 2016

a) ĐKXĐ: x\(\ne\) 0;4

Ta có: Q= \(\left(\frac{4\sqrt{x}}{2+\sqrt{x}}+\frac{8x}{\left(2-\sqrt{x}\right)\left(2+\sqrt{x}\right)}\right):\left(\frac{\sqrt{x}-1}{\sqrt{x}\left(\sqrt{x}-2\right)}-\frac{2}{\sqrt{x}}\right)\)

                   = \(\frac{4\sqrt{x}\cdot\left(2-\sqrt{x}\right)+8x}{\left(2-\sqrt{x}\right)\left(2+\sqrt{x}\right)}:\frac{\sqrt{x}-1-2\cdot\left(\sqrt{x}-2\right)}{\sqrt{x}\left(\sqrt{x}-2\right)}\)

                   =\(\frac{8\sqrt{x}+4x}{\left(2-\sqrt{x}\right)\left(2+\sqrt{x}\right)}\cdot\frac{\sqrt{x}\left(\sqrt{x}-2\right)}{3-\sqrt{x}}\)\(\frac{4\sqrt{x}\cdot\left(2+\sqrt{x}\right)}{2+\sqrt{x}}\cdot\frac{-\sqrt{x}}{3-\sqrt{x}}\)=\(\frac{-4}{3-\sqrt{x}}\)=\(\frac{4}{\sqrt{x}-3}\)

b) Q=-1 => \(\frac{4}{\sqrt{x}-3}=-1\)

<=> \(4=3-\sqrt{x}\)

<=> \(\sqrt{x}=-1\) (vô lí)

Vậy ko tìm được x.

12 tháng 7 2016

kamsamita vui

Bài 3: 

b: \(\Leftrightarrow x^2\left(x+1\right)^2=0\)

hay \(x\in\left\{0;-1\right\}\)

c: \(\Leftrightarrow\left(x-1\right)\left(x^2+x+1\right)=0\)

=>x-1=0

hay x=1

d: \(\Leftrightarrow6x^2-3x-4x+2=0\)

\(\Leftrightarrow\left(2x-1\right)\left(3x-2\right)=0\)

hay \(x\in\left\{\dfrac{1}{2};\dfrac{2}{3}\right\}\)

2:

a: =>x-1=0 hoặc 3x+1=0

=>x=1 hoặc x=-1/3

b: =>x-5=0 hoặc 7-x=0

=>x=5 hoặc x=7

c: =>\(\left[{}\begin{matrix}x-1=0\\x+5=0\\3x-8=0\end{matrix}\right.\Leftrightarrow x\in\left\{1;-5;\dfrac{8}{3}\right\}\)

d: =>x=0 hoặc x^2-1=0

=>\(x\in\left\{0;1;-1\right\}\)

18 tháng 4 2023

Bạn tách ra từng câu thoi nhe .

29 tháng 4 2018

\(a,\left(4\frac{1}{2}-\frac{2}{5}x\right):1\frac{3}{4}=\frac{11}{14}\)

\(\Rightarrow\left(\frac{9}{2}-\frac{2}{5}x\right):\frac{7}{4}=\frac{11}{4}\)

\(\Rightarrow\left(\frac{9}{2}-\frac{2}{5}x\right)=\frac{11}{4}\cdot\frac{7}{4}\)

\(\Rightarrow\left(\frac{9}{2}-\frac{2}{5}x\right)=\frac{77}{16}\)

\(\Rightarrow\frac{9}{2}-\frac{2}{5}x=\frac{77}{16}\)

\(\Rightarrow-\frac{2}{5}x=\frac{77}{16}-\frac{9}{2}\)

\(\Rightarrow-\frac{2}{5}x=\frac{5}{16}\)

\(\Rightarrow x=\frac{5}{16}:\left(-\frac{2}{5}\right)\)

\(\Rightarrow x=-\frac{25}{32}\)

\(b,\frac{2}{3}\cdot x-\frac{2}{5}x=\frac{9}{3}\)

\(\Rightarrow x\left(\frac{2}{3}-\frac{2}{5}\right)=\frac{8}{3}\)

\(\Rightarrow x\cdot\frac{4}{15}=\frac{8}{3}\)

\(\Rightarrow x=\frac{8}{3}:\frac{4}{15}\)

\(\Rightarrow x=10\)

29 tháng 4 2018

\(c,\frac{-2}{3}|x|+1\frac{1}{2}=\frac{2}{5}\)

\(\Rightarrow\frac{-2}{3}|x|+\frac{3}{2}=\frac{2}{5}\)

\(\Rightarrow\frac{-2}{3}|x|=\frac{2}{5}-\frac{3}{2}\)

\(\Rightarrow\frac{-2}{3}|x|=-\frac{11}{10}\)

\(\Rightarrow|x|=\frac{-11}{10}:\frac{-2}{3}\)

\(\Rightarrow|x|=\frac{33}{20}\)

\(\Rightarrow\orbr{\begin{cases}x=\frac{33}{20}\\x=-\frac{33}{20}\end{cases}}\)

\(d,|2x-\frac{1}{3}|+\frac{1}{6}=\frac{3}{4}\)

\(\Rightarrow|2x-\frac{1}{3}|=\frac{3}{4}-\frac{1}{6}\)

\(\Rightarrow|2x-\frac{1}{3}|=\frac{7}{12}\)

\(\Rightarrow\orbr{\begin{cases}2x-\frac{1}{3}=\frac{7}{12}\\2x-\frac{1}{3}=-\frac{7}{12}\end{cases}\Rightarrow\orbr{\begin{cases}2x=\frac{11}{12}\\2x=-\frac{1}{4}\end{cases}}\Rightarrow\orbr{\begin{cases}x=\frac{11}{24}\\x=-\frac{1}{8}\end{cases}}}\)