giải BPT \(\dfrac{2x-1}{3}+\dfrac{x-1}{2}\le3\)
Giải bpt sau
a, \(\left(x+3\right)^2-\left(x-3\right)^2\le3\left(x+1
\right)\)
b, \(2\left(x+3\right).\left(x+4\right)>\left(x-2\right)^2+\left(x-1\right)^2\)
c, \(5x^2-18x+19-\left(2x-3\right)^2>0\)
d, \(\dfrac{\left(3x-2\right)^2}{4}-\dfrac{3\left(x-2\right)}{8}-1>\dfrac{-15x\left(5-3x\right)}{2}\)
e, \(2x^2+2x+2-\dfrac{15\left(x-1\right)}{2}-1>2x\left(x-2,75\right)\)
g, \(\dfrac{5x^2-3}{5}+\dfrac{3x-1}{4}< \dfrac{x\left(2x+3\right)}{2}-5\)
giải các bpt sau
a,\(\dfrac{x^2+2x-13}{x-1}< 1\)
b,\(\dfrac{3x^2+x-4}{x-1}< 3\)
c,\(\dfrac{2x^2-3x+1}{x+2}>0\)
d,\(\dfrac{x^2-x-6}{x^2-1}\le1\)
a: =>\(\dfrac{x^2+2x-13-x+1}{x-1}< 0\)
=>\(\dfrac{x^2+x-12}{x-1}< 0\)
=>\(\dfrac{\left(x+4\right)\left(x-3\right)}{x-1}< 0\)
=>1<x<3 hoặc x<-4
b: =>\(\dfrac{3x^2+4x-3x-4}{x-1}< 3\)
=>3x+4<3
=>3x<-1
=>x<-1/3
c: TH1: 2x^2-3x+1>0 và x+2>0
=>(2x-1)(x-1)>0 và x+2>0
=>x>1
TH2: (2x-1)(x-1)<0 và x+2<0
=>x<-2 và 1/2<x<1
=>Loại
Giải các BPT sau
a) \(\dfrac{3-2x}{5}\)-\(\dfrac{4x+1}{3}\)<\(\dfrac{-2+x}{2}\)-\(\dfrac{1}{4}\)
b) (x+2)2-(5+x)2 < hoặc = -2(4x+5)
Giải bpt
\(\dfrac{x+2}{3x+1}\ge\dfrac{x-2}{2x-1}\)
ĐK: \(x\ne\dfrac{1}{2};x\ne-\dfrac{1}{3}\)
\(\dfrac{x+2}{3x+1}\ge\dfrac{x-2}{2x-1}\)
\(\Leftrightarrow\dfrac{\left(x+2\right)\left(2x-1\right)-\left(x-2\right)\left(3x+1\right)}{\left(3x+1\right)\left(2x-1\right)}\ge0\)
\(\Leftrightarrow\dfrac{2x^2+3x-2-3x^2+5x+2}{6x^2-x-1}\ge0\)
\(\Leftrightarrow\dfrac{-x^2+8x}{6x^2-x-1}\ge0\)
\(\Leftrightarrow\left\{{}\begin{matrix}-x^2+8x\ge0\\6x^2-x-1>0\end{matrix}\right.\left(1\right)\) hoặc \(\left\{{}\begin{matrix}-x^2+8x\le0\\6x^2-x-1< 0\end{matrix}\right.\left(2\right)\)
\(\left(1\right)\Leftrightarrow\left\{{}\begin{matrix}0\le x\le8\\\left[{}\begin{matrix}x>\dfrac{1}{2}\\x< -\dfrac{1}{3}\end{matrix}\right.\end{matrix}\right.\Leftrightarrow\dfrac{1}{2}< x\le8\)
\(\left(2\right)\Leftrightarrow\left\{{}\begin{matrix}\left[{}\begin{matrix}x\le0\\x\ge8\end{matrix}\right.\\-\dfrac{1}{3}< x< \dfrac{1}{2}\end{matrix}\right.\Leftrightarrow-\dfrac{1}{3}< x\le0\)
Vậy ...
giải BPT :
\(\dfrac{2x-1}{3}-\dfrac{x+3}{2}\le1\)
\(\dfrac{2x-1}{3}\)-\(\dfrac{x+3}{2}\)\(\le\)1
<=>\(\dfrac{2\left(2x-1\right)}{6}\)+\(\dfrac{3\left(x+3\right)}{6}\)\(\le\)\(\dfrac{6}{6}\)
=>4x -2 +3x+9\(\le\)6
<=>7x+7\(\le\)6
<=>7x\(\le\)6-7
<=>7x\(\le\)-1
<=>x\(\le\)\(\dfrac{-1}{7}\)
vậy bất phương trình có nghiệm là x\(\le\)\(\dfrac{-1}{7}\)
\(\dfrac{2x-1}{3}\)-\(\dfrac{x+3}{2}\)\(\le\)1
<=>\(\dfrac{2\left(2x-1\right)}{6}\)-\(\dfrac{3\left(x+3\right)}{6}\le\dfrac{6}{6}\)
=>4x-2-3x-9\(\le\)6
<=>x-11\(\le\)6
<=>x\(\le\)6+11
<=>x\(\le\)17
Vậy bất phương trình có nghiệm là x\(\le\)17
Tìm nghiệm của bpt sau: \(\dfrac{x+2}{x-2}-\dfrac{1}{x}=\dfrac{2}{x^2-2x}\)
Giải giúp mik với
\(\dfrac{x+2}{x-2}-\dfrac{1}{x}=\dfrac{2}{x^2-2x}\) ; ĐKXĐ: \(x\ne0;x\ne2\)
\(\Leftrightarrow\dfrac{x\left(x+2\right)}{x\left(x-2\right)}-\dfrac{x-2}{x\left(x-2\right)}=\dfrac{2}{x\left(x-2\right)}\)
\(\Leftrightarrow\dfrac{x^2+2x-x+2}{x\left(x-2\right)}=\dfrac{2}{x\left(x-2\right)}\)
\(\Leftrightarrow x^2+2x-x+2-2=0\)
\(\Leftrightarrow x^2+x=0\)
\(\Leftrightarrow x\left(x+1\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x+1=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=0\left(ktm\right)\\x=-1\left(tm\right)\end{matrix}\right.\)
Vậy: nghiệm của bpt S = {-1}
\(\Leftrightarrow\dfrac{\left(x+2\right)x}{x\left(x-2\right)}-\dfrac{x-2}{x\left(x-2\right)}=\dfrac{2}{x\left(x-2\right)}\) ∀x≠{0;2}
\(\Leftrightarrow x^2+2x-\left(x-2\right)=2\\ \Leftrightarrow x^2+2x-x+2-2=0\\ \Leftrightarrow x^2+x=0\)
\(\Rightarrow\left\{{}\begin{matrix}x=0\\x=-1\end{matrix}\right.\)
xét điều kiện, ta loại x = 0, nhận x = -1
Ta có: \(\dfrac{x+2}{x-2}-\dfrac{1}{x}=\dfrac{2}{x^2-2x}\)
\(\Leftrightarrow\dfrac{x^2+2x-x+2}{\left(x-2\right)x}=\dfrac{2}{x\left(x-2\right)}\)
Suy ra: \(x^2+x=0\)
\(\Leftrightarrow x\left(x+1\right)=0\)
hay x=-1
giúp mình giải bpt vs
\(\dfrac{\left|2x-1\right|-x}{2x}>1;\dfrac{2-\left|x-2\right|}{x^2-1}\ge0;\dfrac{\sqrt{x+4}-2}{4-9x^2}\le0;\dfrac{x^2-2x-3}{\sqrt[3]{3x-1}+\sqrt[3]{4-5x}}\ge0;\)\(3x^2-10x+3\ge0;\left(\sqrt{2}-x\right)\left(x^2-2\right)\left(2x-4\right)< 0;\dfrac{1}{x+9}-\dfrac{1}{x}>\dfrac{1}{2};\dfrac{2}{1-2x}\le\dfrac{3}{x+1}\)
Giai các bpt sau
a,\(\dfrac{x-1}{2}-\dfrac{7x+3}{15}\le\dfrac{2x+1}{3}+\dfrac{3-2x}{5}\)
b,\(\dfrac{2x+1}{-3}-\dfrac{2x^2+3}{-4}>\dfrac{x\left(5-3x\right)}{-6}-\dfrac{4x+1}{-5}\)
a: \(\Leftrightarrow15\left(x-1\right)-2\left(7x+3\right)\le10\left(2x+1\right)+6\left(3-2x\right)\)
\(\Leftrightarrow15x-15-14x-6\le20x+10+18-12x\)
=>x-21<=8x+28
=>-7x<=49
hay x>=-7
b: \(\Leftrightarrow20\left(2x+1\right)-15\left(2x^2+3\right)< 10x\left(5-3x\right)-12\left(4x+1\right)\)
\(\Leftrightarrow40x+20-30x^2-45< 50x-30x^2-48x-12\)
=>40x-25<2x-12
=>38x<13
hay x<13/38
\(a,\dfrac{x-1}{2}-\dfrac{7x+3}{15}\le\dfrac{2x+1}{3}+\dfrac{3-2x}{5}\\ \Leftrightarrow\dfrac{15\left(x-1\right)}{30}-\dfrac{2\left(7x+3\right)}{30}\le\dfrac{10\left(2x+1\right)}{30}+\dfrac{6\left(3-2x\right)}{30}\\ \Leftrightarrow15x-15-14x-6\le20x+10+18-12x\\ \Leftrightarrow x-21\le8x+28\\ \Leftrightarrow7x+49\ge0\\ \Leftrightarrow x\ge-7\)
\(b,\dfrac{2x+1}{-3}-\dfrac{2x^2+3}{-4}>\dfrac{x\left(5-3x\right)}{-6}-\dfrac{4x+1}{-5}\\ \Leftrightarrow\dfrac{20\left(2x+1\right)}{-60}-\dfrac{15\left(2x^2+3\right)}{-60}>\dfrac{10x\left(5-3x\right)}{-60}-\dfrac{12\left(4x+1\right)}{-60}\\ \Leftrightarrow40x+20-30x^2-45>50x-30x^2-48x-12\\ \Leftrightarrow38x-13>0\\ \Leftrightarrow x>\dfrac{13}{38}\)
Giai các bpt sau
a,\(\dfrac{5x^2-3}{5}+\dfrac{3x-1}{4}< \dfrac{x\left(2x+3\right)}{2}-5\)
b,\(\dfrac{5x-2}{-3}\)\(-\dfrac{2x^2-x}{-2}>\dfrac{x\left(1-3x\right)}{-3}-\dfrac{5x}{-4}\)
a: \(\Leftrightarrow4\left(5x^2-3\right)+5\left(3x-1\right)< 10x\left(2x+3\right)-100\)
\(\Leftrightarrow20x^2-12x+15x-5< 20x^2+30x-100\)
=>3x-5<=30x-100
=>30x-100>3x-5
=>27x>95
hay x>95/27
b: \(\Leftrightarrow4\left(5x-2\right)-6\left(2x^2-x\right)< 4x\left(1-3x\right)-15x\)
\(\Leftrightarrow20x-8-12x^2+6x< 4x-12x^2-15x\)
=>26x-8<-11x
=>37x<8
hay x<8/37