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a. \(5.\left(x-2\right)+3.\left(x-2\right)=0\)
\(\Rightarrow8.\left(x-2\right)=0\)
\(\Rightarrow x-2=0:8\)
\(\Rightarrow x-2=0\)
\(\Rightarrow x=2\)
Vậy...
b. \(\dfrac{2}{3}+\dfrac{5}{2}:x=\dfrac{2}{4}\)
\(\Rightarrow\dfrac{5}{2}:x=\dfrac{2}{4}-\dfrac{2}{3}\)
\(\Rightarrow\dfrac{5}{2}:x=\dfrac{-1}{6}\)
\(\Rightarrow x=\dfrac{5}{2}:\dfrac{-1}{6}=-15\)
Vậy...
c. \(2.\left(x-\dfrac{1}{7}\right)=0\)
\(\Rightarrow x-\dfrac{1}{7}=0:2\)
\(\Rightarrow x-\dfrac{1}{7}=0\)
\(\Rightarrow x=\dfrac{1}{7}\)
Vậy...
d. \(\dfrac{11}{20}-\left(\dfrac{2}{5}+x\right)=\dfrac{2}{3}\)
\(\Rightarrow\dfrac{2}{5}+x=\dfrac{11}{12}:\dfrac{2}{3}\)
\(\Rightarrow\dfrac{2}{5}+x=\dfrac{1}{4}\)
\(\Rightarrow x=\dfrac{1}{4}-\dfrac{2}{5}=\dfrac{-3}{20}\)
Vậy...
e. \(\dfrac{3}{4}+\dfrac{1}{4}:x=\dfrac{2}{5}\)
\(\Rightarrow\dfrac{1}{4}:x=\dfrac{2}{5}-\dfrac{3}{4}\)
\(\Rightarrow\dfrac{1}{4}:x=\dfrac{-7}{20}\)
\(\Rightarrow x=\dfrac{1}{4}:\dfrac{-7}{20}=\dfrac{-5}{7}\)
Vậy...
g. \(\dfrac{2}{3}x+\dfrac{5}{7}=\dfrac{3}{10}\)
\(\Rightarrow\dfrac{2}{3}x=\dfrac{3}{10}-\dfrac{5}{7}\)
\(\Rightarrow\dfrac{2}{3}x=\dfrac{-29}{70}\)
\(\Rightarrow x=\dfrac{-29}{70}:\dfrac{2}{3}=\dfrac{-87}{140}\)
Vậy...
Bài giải
a, \(\left(3x-1\right)\left(x+1\right)>0\)
Khi \(\orbr{\begin{cases}3x-1< 0\\x+1< 0\end{cases}}\Rightarrow\orbr{\begin{cases}3x< 1\\x< -1\end{cases}}\Rightarrow\orbr{\begin{cases}x< \frac{1}{3}\\x< -1\end{cases}}\)
Hoặc \(\orbr{\begin{cases}3x-1>0\\x+1>0\end{cases}}\Rightarrow\orbr{\begin{cases}3x>1\\x>-1\end{cases}}\Rightarrow\orbr{\begin{cases}x>\frac{1}{3}\\x>-1\end{cases}}\)
b, \(\left(x+2\right)^2\left(x-3\right)\le0\)
\(\Rightarrow\text{ }\left(x+2\right)^2\text{ và }\left(x-3\right)\) đối nhau
Mà \(\left(x+2\right)^2\ge0\) nên \(\hept{\begin{cases}\left(x+2\right)^2\ge0\\x-3\le0\end{cases}}\Rightarrow\hept{\begin{cases}x+2\ge0\\x\le3\end{cases}}\Rightarrow\hept{\begin{cases}x\ge-2\\x\le3\end{cases}}\text{ }\left(\text{ loại}\right)\)
\(\Rightarrow\text{ }x\in\varnothing\)
c, \(\left(x-\frac{1}{3}\right)^5=4\left(x-\frac{1}{3}\right)^3\)
\(\left(x-\frac{1}{3}\right)^5-4\left(x-\frac{1}{3}\right)^3=0\)
\(\left(x-\frac{1}{3}\right)^3\left[\left(x-\frac{1}{3}\right)^2-4\right]=0\)
\(\Rightarrow\orbr{\begin{cases}\left(x-\frac{1}{3}\right)^3=0\\\left(x-\frac{1}{3}\right)^2-4=0\end{cases}}\Rightarrow\orbr{\begin{cases}x-\frac{1}{3}=0\\\left(x-\frac{1}{3}\right)^2=4=\left(\pm2\right)^2\end{cases}}\Rightarrow\orbr{\begin{cases}x=\frac{1}{3}\\x=-\frac{5}{3}\text{ ; }x=\frac{7}{3}\end{cases}}\)
\(\Rightarrow\text{ }x\in\left\{\frac{1}{3}\text{ ; }-\frac{5}{3}\text{ ; }\frac{7}{3}\right\}\)
a) \(|x+\frac{3}{4}|+|y-\frac{1}{5}|+|x+y+z|=0\)
\(\Rightarrow|x+\frac{3}{4}|=|y-\frac{1}{5}|=|x+y+z|=0\)
\(\Rightarrow|x+\frac{3}{4}|=0\) \(\Rightarrow|y-\frac{1}{5}|=0\) \(\Rightarrow|x+y+z|=0\)
\(\Rightarrow x+\frac{3}{4}=0\) \(\Rightarrow y-\frac{1}{5}=0\) \(\Rightarrow x+y+z=0\)
\(x=\frac{-3}{4}\) \(y=\frac{1}{5}\) thay x=-3/4; y=1/5 vào biểu thức trên
ta có \(\frac{-3}{4}+\frac{1}{5}+z=0\)
\(z=0-\frac{-3}{4}-\frac{1}{5}\)
VẬY X=-3/4; Y=1/5; Z=11/20
B) \(|3x-4|+\left|3y-5\right|=0\)
\(\Rightarrow\left|3x-4\right|=\left|3y-5\right|=0\)
\(\Rightarrow\left|3x-4\right|=0\) \(\Rightarrow\left|3y-5\right|=0\)
\(3x-4=0\) \(3y-5=0\)
\(3x=4\) \(3y=5\)
\(x=\frac{4}{3}\) \(y=\frac{5}{3}\)
VẬY X= 4/3; Y=5/3
C) \(\left|x+\frac{3}{4}\right|+\left|y-\frac{2}{5}\right|+\left|z+\frac{1}{2}\right|< 0\)
ĐỂ \(\left|x+\frac{3}{4}\right|+\left|y-\frac{2}{5}\right|+\left|z+\frac{1}{2}\right|< 0\)
\(\Rightarrow\left|x+\frac{3}{4}\right|;\left|y-\frac{2}{5}\right|;\left|z+\frac{1}{2}\right|< 0\)
MÀ GIÁ TRỊ TUYỆT ĐỐI LUÔN MANG SỐ NGUYÊN DƯƠNG
\(\Rightarrow x;y;z\in\varnothing\)
d) \(\left|x+\frac{1}{5}\right|+\left|3-y\right|=0\)
\(\Rightarrow\left|x+\frac{1}{5}\right|=\left|3-y\right|=0\)
\(\Rightarrow\left|x+\frac{1}{5}\right|=0\) \(\Rightarrow\left|3-y\right|=0\)
\(x+\frac{1}{5}=0\) \(3-y=0\)
\(x=\frac{-1}{5}\) \(y=3\)
VẬY X= -1/5; Y=3
CHÚC BN HỌC TỐT!!!!!!!
Ta có :
\(\left|x+\frac{3}{4}\right|+\left|y-\frac{1}{5}\right|+\left|x+y+z\right|=0\)
\(\Leftrightarrow\)\(\hept{\begin{cases}x+\frac{3}{4}=0\\y-\frac{1}{5}=0\\x+y+z=0\end{cases}}\Leftrightarrow\hept{\begin{cases}x=\frac{-3}{4}\\y=\frac{1}{5}\\z=0-\frac{-3}{4}-\frac{1}{5}\end{cases}}\)
\(\Leftrightarrow\)\(\hept{\begin{cases}x=\frac{-3}{4}\\y=\frac{1}{5}\\z=\frac{11}{20}\end{cases}}\)
Vậy \(x=\frac{-3}{4};y=\frac{1}{5};z=\frac{11}{20}\)
a, \(\left(5x-1\right)\left(2x-\frac{1}{3}\right)=0\)
\(\Rightarrow\orbr{\begin{cases}5x-1=0\\2x-\frac{1}{3}=0\end{cases}\Rightarrow}\orbr{\begin{cases}5x=1\\2x=\frac{1}{3}\end{cases}\Rightarrow}\orbr{\begin{cases}x=\frac{1}{5}\\x=\frac{1}{6}\end{cases}}\)
b. \(\left(x^2+1\right)\left(x-4\right)=0\)
\(\Rightarrow\orbr{\begin{cases}x^2+1=0\\x-4=0\end{cases}\Rightarrow}\orbr{\begin{cases}x^2=-1\left(Voly\right)\\x=4\end{cases}\Rightarrow x=4}\)
c, \(2x^2-\frac{1}{3}x=0\)
\(\Leftrightarrow x\left(2x-\frac{1}{3}\right)=0\)
\(\Rightarrow\orbr{\begin{cases}x=0\\2x-\frac{1}{3}=0\end{cases}}\Rightarrow\orbr{\begin{cases}x=0\\x=\frac{1}{6}\end{cases}}\)
d, \(\left(\frac{4}{5}\right)^{5x}=\left(\frac{4}{5}\right)^7\)
\(\Rightarrow5x=7\)
\(\Rightarrow x=\frac{7}{5}\)
e, Ta có: \(A=\frac{x+5}{x-2}=\frac{\left(x-2\right)+7}{x-2}=1+\frac{7}{x-2}\)
Để A ∈ Z <=> (x - 2) ∈ Ư(7) = { ±1; ±7 }
| x - 2 | 1 | -1 | 7 | -7 |
| x | 3 | 1 | 9 | -5 |
Vậy....
a) \(\left(5x-1\right)\left(2x-\frac{1}{3}\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}5x-1=0\\2x-\frac{1}{3}=0\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}5x=1\\2x=\frac{1}{3}\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x=\frac{1}{5}\\x=\frac{1}{6}\end{cases}}\)
Vậy : ....
b) \(\left(x^2+1\right)\left(x-4\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}x^2+1=0\\x-4=0\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x^2=-1\left(loại\right)\\x=4\end{cases}}\)
c) \(2x^2-\frac{1}{3}x=0\)
\(\Leftrightarrow x\left(2x-\frac{1}{3}\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}x=0\\2x-\frac{1}{3}=0\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x=0\\x=\frac{1}{6}\end{cases}}\)
Vậy :...
a)\(\dfrac{1}{6}x+\dfrac{1}{10}x-\dfrac{4}{15}x+1=0\)
\(\left(\dfrac{1}{6}+\dfrac{1}{10}-\dfrac{4}{15}\right).x+1=0\)
\(\left(\dfrac{5}{30}+\dfrac{3}{30}-\dfrac{8}{30}\right).x+1=0\)
\(0.x+1=0\)
\(0.x=-1\)
=> Không có giá trị nào của x.
Vậy...
b)\(\left(\dfrac{1}{7}x-\dfrac{2}{7}\right).\left(-\dfrac{1}{5}x+\dfrac{3}{5}\right).\left(\dfrac{1}{3}x+\dfrac{4}{3}\right)=0\)
=> \(\dfrac{1}{7}x-\dfrac{2}{7}=0hoặc-\dfrac{1}{5}x+\dfrac{3}{5}=hoăc\dfrac{1}{3}x+\dfrac{4}{3}=0\)
+)\(~\dfrac{1}{7}x-\dfrac{2}{7}=0\) +) \(-\dfrac{1}{5}x+\dfrac{3}{5}=0\) +) \(\dfrac{1}{3}x+\dfrac{4}{3}=0\)
\(\dfrac{1}{7}x=-\dfrac{2}{7}\) \(-\dfrac{1}{5}x=-\dfrac{3}{5}\) \(\dfrac{1}{3}x=-\dfrac{4}{3}\)
\(x=2\) \(x=3\) \(x=-4\)
Vậy...
a 1/6x+1/10x-4/15x+1=0
(1/6+1/10-4/15)x+1=0
0x+1=0
0x=-1
x=-1/0
Vậy không có x (vì không có số nào chia cho 0)
a: =>|x+3/5|=|x-7/3|
=>x-7/3=x+3/5 hoặc x-7/3=-x-3/5
=>2x=-3/5+7/3=26/15
=>x=13/15
b: \(\Leftrightarrow\left|6x-1\right|=\left|3x-\dfrac{3}{2}\right|\)
=>6x-1=3x-3/2 hoặc 6x-1=3/2-3x
=>3x=-3/2+1=-1/2 hoặc 9x=5/2
=>x=-1/6 hoặc x=5/18
c: \(\Leftrightarrow\left|\dfrac{3}{2}x-3\right|=\left|\dfrac{15}{2}x+5\right|\)
=>3/2x-3=15/2x+5 hoặc 3/2x-3=-15/2x-5
=>-6x=8 hoặc 9x=-2
=>x=-2/9 hoặc x=-4/3
a)\(\frac{1}{3}+\frac{1}{2}:x=\frac{1}{5}\)
\(\frac{1}{2}:x=\frac{1}{5}-\frac{1}{3}\)
\(\frac{1}{2}:x=-\frac{2}{15}\)
\(x=-\frac{15}{4}\)
b)\(\frac{1}{3}x+\frac{2}{5}\left(x+1\right)=0\)
\(\frac{1}{3}x+\frac{2}{5}x+\frac{2}{5}=0\)
\(\frac{11}{15}x=-\frac{2}{5}\)
\(x=-\frac{6}{11}\)
c)\(\left(x+\frac{1}{2}\right)\left(x-\frac{3}{4}\right)=0\)
\(\Rightarrow\orbr{\begin{cases}x+\frac{1}{2}=0\\x-\frac{3}{4}=0\end{cases}\Rightarrow}\orbr{\begin{cases}x=-\frac{1}{2}\\x=\frac{3}{4}\end{cases}}\)