\(\frac{2}{x-3}\le\frac23\)
Giải bpt
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\(\dfrac{3\left(x-1\right)}{x+2}< 3\)
⇔ \(\dfrac{3x-3}{x+2}-3< 0\)
⇔ \(\dfrac{3x-3-3x-6}{x+2}< 0\)
⇔ \(\dfrac{-9}{x+2}\) < 0
Do : - 9 < 0
⇒ x + 2 > 0
⇒ x > - 2
KL.....
\(\dfrac{3\left(x+1\right)}{x+2}< 3\)
\(\Leftrightarrow\dfrac{3\left(x+1\right)}{x+2}-3< 0\)
\(\Leftrightarrow\dfrac{3x+3-3\left(x+2\right)}{x+2}< 0\)
\(\Leftrightarrow\dfrac{-3}{x+2}< 0\)
Vì -3 < 0
\(\Rightarrow x+2>0\)
\(\Leftrightarrow x>-2\)
Vậy BPT có nghiệm x > - 2
2x +\(\frac{2}{3}\)< 2 + x -\(\frac{2}{2}\)
<=> 2x - x < 2 - \(\frac{2}{2}\)-\(\frac{2}{3}\)
<=> x < 2 -\(\frac{6}{6}\)-\(\frac{4}{6}\)
<=> x < 2 -\(\frac{2}{6}\)
<=> x < 2 - \(\frac{1}{3}\)
<=> x <\(\frac{5}{3}\)
#Học tốt!!!
~NTTH~
\(\frac{2x+2}{3}< 2+\frac{x-2}{2}\)
<=> \(\frac{2\left(2x+2\right)}{6}< \frac{12}{6}+\frac{3\left(x-2\right)}{6}\)
<=> \(\frac{4x+4}{6}< \frac{12}{6}+\frac{3x-6}{6}\)
Khử mẫu
<=> 4x + 4 < 12 + 3x - 6
<=> 4x - 3x < 12 - 6 - 4
<=> x < 2
Vậy nghiệm của bất phương trình là x < 2
\(3^{x^2-x-6}<4\)
bạn ơi góp ý câu a là x phải nguên=>x^2-x-6=0 hoặc =1
x^2-x-6=0<=>x^2-x-7=0(l vì x không nguyên)
TH =0 thì xem câu b
b)3^(x^2-x-6)=1
<=>x^2-x-6=0
<=>(x-3)(x+2)=0
<=>x=3 hoặc x=-2
a) \(x\in\left(\frac{1}{2}-\frac{\sqrt{25\ln3+8\ln2}}{2\sqrt{\ln3}};\frac{\sqrt{25\ln3+8\ln2}}{2\sqrt{\ln3}}+\frac{1}{2}\right)\)
b) 3x2 - x - 6 - 1 = 0
x = -2
x = 3
\(\left(-x\right)^2< 3\)
\(\Leftrightarrow x^2< 3\)
\(\Leftrightarrow x^2-3< 0\)
\(\Leftrightarrow\left(x-\sqrt{3}\right)\left(x+\sqrt{3}\right)< 0\)
\(\Leftrightarrow\left[{}\begin{matrix}\left\{{}\begin{matrix}x-\sqrt{3}>0\\x+\sqrt{3}< 0\end{matrix}\right.\\\left\{{}\begin{matrix}x-\sqrt{3}< 0\\x+\sqrt{3}>0\end{matrix}\right.\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}\left\{{}\begin{matrix}x>\sqrt{3}\\x< -\sqrt{3}\end{matrix}\right.\\\left\{{}\begin{matrix}x< \sqrt{3}\\x>-\sqrt{3}\end{matrix}\right.\end{matrix}\right.\)
Vậy \(x\in\left\{\sqrt{3};-\sqrt{3}\right\}\)
a: \(\dfrac{2x-3}{35}+\dfrac{x\left(x-2\right)}{7}< \dfrac{x^2}{7}-\dfrac{2x-3}{5}\)
\(\Leftrightarrow2x-3+5x\left(x-2\right)< 5x^2-7\left(2x-3\right)\)
\(\Leftrightarrow2x-3+5x^2-10x< 5x^2-14x+21\)
=>-8x-3<-14x+21
=>6x<24
hay x<4
3: \(\dfrac{3x-2}{4}< \dfrac{3x+3}{6}\)
\(\Leftrightarrow3\left(3x-2\right)< 2\left(3x+3\right)\)
=>9x-6<6x+6
=>3x<12
hay x<4
a) \(\dfrac{2x-3}{35}\) + \(\dfrac{x\left(x-2\right)}{7}\) < \(\dfrac{x^2}{7}\) - \(\dfrac{2x-3}{5}\)
<=> \(\dfrac{2x-3}{35}\) + \(\dfrac{5x\left(x-2\right)}{7.5}\) < \(\dfrac{5x^2}{7.5}\) - \(\dfrac{7\left(2x-3\right)}{7.5}\)
<=> 2x-3 + 5x2-10x < 5x2 - 14x + 21
<=> 5x2 - 5x2 + 2x -10x + 14x < 21 + 3
<=> 6x < 24
<=> x < 4
vậy bpt có tập nghiệm S={ x < 4 }
\(\frac{2}{x-3}\) ≤ \(\frac23\)
\(\frac{1}{x-3}\) ≤ \(\frac13\)
\(\frac{1}{x-3}-\frac13\) ≤ 0
\(\frac{3-x+3}{3\left(x-3\right)}\) ≤ 0
\(\frac{\left(3+3\right)-x}{3\left(x-3\right)}\) ≤ 0
\(\frac{6-x}{3\left(x-3\right)}\) ≤ 0
6 - \(x\) = 0 ⇒ \(x=6\); \(x-3=0\) ⇒ \(x=3\)
Lập bảng xét dấu ta có:
\(x\)
3 6
-\(x+6\)
+ + 0 -
3\(x\) - 9
- 0 + +
3(\(\)\(x-3).\left(-x+6\right)\)
- || + 0 -
Theo bảng trên ta có: \(x\) ≥ 6 hoặc \(x\) < 3