Tìm x ,biết
\(2x^2-2x=\left(x-1\right)^2\)
Tìm x biết :
\(\left(x-1\right)\left(x^2+x+1\right)+\left(2x\right)\left(4-2x+x^2\right)=5-x\)
tìm x , biết
\(a,\left|2x-3\right|-\left|3x+2\right|=0\\ b,\left|\dfrac{1}{2}x\right|=3-2x\)
a)TH1: \(2x-3>0;3x+2>0\)
\(=>2x-3-3x-2=0\\ =>-x-5=0\\ =>-x=5=>x=-5\)
TH2: \(2x-3< 0;3x+2< 0\)
\(=>-2x+3+3x+2=0\\ =>x+5=0\\ =>x=-5\)
Cả 2 TH ra \(x=-5=>x=-5\)
b)TH1 \(\dfrac{1}{2}x>0\)
\(=>\dfrac{1}{2}x=3-2x\\ =>3-2x-\dfrac{1}{2}x=0\\ =>\dfrac{4}{2}x-\dfrac{1}{2}x=3\\ =>\dfrac{3}{2}x=3\\ =>x=2\)
TH2 \(\dfrac{1}{2}x< 0\)
\(=>-\dfrac{1}{2}x=3-2x\\ =>3-2x+\dfrac{1}{2}x=0\\ =>\dfrac{4}{2}x+\dfrac{1}{2}x=3\\ =>\dfrac{5}{2}x=3\\ =>x=\dfrac{6}{5}\)
\(=>x=2;\dfrac{6}{5}\)
Tìm x biết :
\(\sqrt{\left(2x-1\right)}^2=5\)
gợi ý:
\(\sqrt{\left(2x-1\right)}^2=\left|2x-1\right|\)
cần giải hai phương trình
2x-1=5
2x-1=-5
\(\Leftrightarrow\left|2x-1\right|=5\Leftrightarrow\left[{}\begin{matrix}2x-1=5\\1-2x=5\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=3\\x=-2\end{matrix}\right.\)
BÀI 6 tìm x
1,\(2x\left(x-5\right)-\left(3x+2x^2\right)=0\) 2,\(x\left(5-2x\right)+2x\left(x-1\right)=13\)
3,\(2x^3\left(2x-3\right)-x^2\left(4x^2-6x+2\right)=0\) 4,\(5x\left(x-1\right)-\left(x+2\right)\left(5x-7\right)=6\)
5,\(6x^2-\left(2x-3\right)\left(3x+2\right)=1\) 6,\(2x\left(1-x\right)+5=9-2x^2\)
1: \(\Leftrightarrow2x^2-10x-3x-2x^2=0\)
=>-13x=0
=>x=0
2: \(\Leftrightarrow5x-2x^2+2x^2-2x=13\)
=>3x=13
=>x=13/3
3: \(\Leftrightarrow4x^4-6x^3-4x^3+6x^3-2x^2=0\)
=>-2x^2=0
=>x=0
4: \(\Leftrightarrow5x^2-5x-5x^2+7x-10x+14=6\)
=>-8x=6-14=-8
=>x=1
`1)2x(x-5)-(3x+2x^2)=0`
`<=>2x^2-10x-3x-2x^2=0`
`<=>-13x=0`
`<=>x=0`
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`2)x(5-2x)+2x(x-1)=13`
`<=>5x-2x^2+2x^2-2x=13`
`<=>3x=13<=>x=13/3`
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`3)2x^3(2x-3)-x^2(4x^2-6x+2)=0`
`<=>4x^4-6x^3-4x^4+6x^3-2x^2=0`
`<=>x=0`
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`4)5x(x-1)-(x+2)(5x-7)=0`
`<=>5x^2-5x-5x^2+7x-10x+14=0`
`<=>-8x=-14`
`<=>x=7/4`
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`5)6x^2-(2x-3)(3x+2)=1`
`<=>6x^2-6x^2-4x+9x+6=1`
`<=>5x=-5<=>x=-1`
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`6)2x(1-x)+5=9-2x^2`
`<=>2x-2x^2+5=9-2x^2`
`<=>2x=4<=>x=2`
tìm x biết : x.(x+2/3)-x.(x-3/4)=7/12
b)\(\sqrt{x^2}+1\)=x+2
c)\(\left(2x+1\right)^5\)=\(\left(2x+1\right)^{2019}\)
mọi người ơi câu b là giá trị tuyệt đối của x^2 -1 nha
giúp mình mình tick cho
a) \(\Leftrightarrow x^2+\dfrac{2}{3}x-x^2+\dfrac{3}{4}x=\dfrac{7}{12}\)
\(\Leftrightarrow\dfrac{17}{12}x=\dfrac{7}{12}\Leftrightarrow x=\dfrac{7}{17}\)
c) \(\Leftrightarrow\left[{}\begin{matrix}2x+1=-1\\2x+1=1\\2x+1=0\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=-1\\x=0\\x=-\dfrac{1}{2}\end{matrix}\right.\)
1,tìm x biết:\(\left|2x+3\right|+\left|2x-1\right|=\dfrac{8}{3.\left(x+1\right)^2+2}\)
\(VT=\left|2x+3\right|+\left|2x-1\right|=\left|2x+3\right|+\left|1-2x\right|\ge\left|2x+3+1-2x\right|=\left|4\right|=4\)
\(VP=\frac{8}{3\left(x+1\right)^2+2}\le\frac{8}{2}=4\)
\(VT\ge VP\)
Dấu "=" xảy ra \(\Leftrightarrow\)\(\hept{\begin{cases}\left(2x+3\right)\left(1-2x\right)\ge0\left(1\right)\\\left(x+1\right)^2=0\left(2\right)\end{cases}}\)
\(\left(2\right)\)\(\Leftrightarrow\)\(x=-1\) ( thỏa mãn\(\left(1\right)\) )
...
Tìm x biết
a) \(\left(x+3\right)^3-x\left(3x+1\right)^2+\left(2x+1\right)\left(4x^2-2x+1\right)-3x^2=54\)
Tìm x,biết
\(\left(x+3\right)^3-x\left(3x+1\right)^2+\left(2x+1\right)\left(4x^2-2x+1\right)-3x^2=42\) 42
tìm x biết :
a) \(\left|x+\dfrac{1}{2}\right|\)=\(\dfrac{5}{2}\) b) \(\left|2x-\dfrac{2}{3}\right|\)+\(\dfrac{1}{3}\)=0 c) |x-2| = 2x + 1
\(\left[{}\begin{matrix}2x-\dfrac{2}{3}=\dfrac{1}{3}\\2x-\dfrac{2}{3}=\dfrac{-1}{3}\end{matrix}\right.\left[{}\begin{matrix}2x=1\\2x=\dfrac{1}{3}\end{matrix}\right.\left[{}\begin{matrix}x=\dfrac{1}{2}\\x=\dfrac{1}{6}\end{matrix}\right.\)
a)\(\left[{}\begin{matrix}x+\dfrac{1}{2}=\dfrac{5}{2}\\x+\dfrac{1}{2}=-\dfrac{5}{2}\end{matrix}\right.\left[{}\begin{matrix}x=2\\x=-3\end{matrix}\right.\)
c)\(\left[{}\begin{matrix}x-2=2x-1\\-x+2=2x-1\end{matrix}\right.\left[{}\begin{matrix}x-2=2x-1\\-x+2=2x-1\end{matrix}\right.\left[{}\begin{matrix}x-2x=-1+2\\-x-2x=-1-2\end{matrix}\right.\left[{}\begin{matrix}-1x=1\\-3x=-3\end{matrix}\right.=>\left[{}\begin{matrix}x=1:\left(-1\right)\\x=-3:\left(-3\right)\end{matrix}\right.=>\left[{}\begin{matrix}x=-1\\x=1\end{matrix}\right.\)