Ta có :
\(\left(x+1\right)\left(x-2\right)< 0\)
\(\Leftrightarrow x+1;x-2\) khác dấu
Mà \(x+1>x-2\)
\(\Leftrightarrow\left\{{}\begin{matrix}x+1>0\\x-2< 0\end{matrix}\right.\) \(\Leftrightarrow\left\{{}\begin{matrix}x=-1\\x=2\end{matrix}\right.\) \(\Leftrightarrow-1< x< 2\)
\(\Leftrightarrow x\in\left\{0;1\right\}\)
Vậy ...
Tìm \(x\in\mathbb{Q}\), biết :
a) \(\left(x+1\right)\left(x-2\right)< 0\)
b) \(\left(x-2\right)\left(x+\dfrac{2}{3}\right)>0\)
Tìm \(x\in Q\), biết rằng :
a) \(\dfrac{11}{12}-\left(\dfrac{2}{5}+x\right)=\dfrac{2}{3}\)
b) \(2x\left(x-\dfrac{1}{7}\right)=0\)
c) \(\dfrac{3}{4}+\dfrac{1}{4}:x=\dfrac{2}{5}\)
Bài 1, Tìm x biết
a)\(\left|x\right|+\left|x+2\right|=0\)
b)\(\left|x\left(x^2-\frac{5}{4}\right)\right|=x\)
1. x : (\(\frac{2}{9}-\frac{1}{5}\))=\(\frac{8}{16}\)
2. a)\(\frac{x-3}{-2}\)>0
b) \(x^2\)+x >0
c) \(\frac{x+3}{x-5}\)<0
1) Tìm x:
a) \(\frac{11}{12}-\frac{5}{12}.\left(\frac{2}{5}+x\right)=\frac{2}{3}\)
b) \(\frac{3}{4}+\frac{1}{4}:x=\frac{2}{5}\)
c) 2x.(x-\(\frac{1}{7}\))=0
d) (x + 1) . (x - 2) < 0
e) (x - 2) . ( x + \(\frac{2}{3}\) ) >0
Tìm \(x\in Q\), biết rằng:
a) \(\dfrac{11}{12}-\left(\dfrac{2}{5}+x\right)=\dfrac{2}{3}\)
b) \(2x.\left(x-\dfrac{1}{7}\right)=0\)
c) \(\dfrac{3}{4}+\dfrac{1}{4}:x=\dfrac{2}{5}\)
Tìm x, y\(\in\)Z, biết:
a) \(\dfrac{5}{x}+\dfrac{y}{4}=\dfrac{1}{8}\)
b) \(\dfrac{1}{x}=\dfrac{1}{6}+\dfrac{y}{3}\)
c) \((x+1)(x-2)<0\)
d) \((x-2)(x+\dfrac{2}{3})>0\)
2. Tìm x, biết
a) \(\dfrac{3}{4}\)+\(\dfrac{1}{4}\): x =\(\dfrac{2}{5}\)
b) 2x.(x -\(\dfrac{1}{7}\))=0
Giúp mình với
Tìm x
a, \(\left(2-x\right)\times\left(\dfrac{4}{5}-x\right)< 0\)
b, \(\left(x-\dfrac{3}{2}\right)\times\left(2\times x-1\right)>0\)
c, \(\left(x-\dfrac{4}{7}\right)\div\left(x+\dfrac{1}{2}\right)>0\)
d, \(\left(2\times x-5\right)\div\left(x+1\dfrac{3}{4}\right)< 0\)
Giúp mk với
