tim x biet : \(\left|2x-5\right|+1=3x\)
tim x biet
\(3x\left(x-1\right)-x\left(3x-2\right)=5\)
\(8x\left(2x+1\right)-4x\left(2x-3\right)=-40\)
\(\left(2x-1\right)\left(3x-1\right)-\left(3x-2\right)\left(2x-1\right)=3\)
a ) \(3x\left(x-1\right)-x\left(3x-2\right)=5\)
\(\Leftrightarrow3x^2-3x-3x^2+2x=5\)
\(\Leftrightarrow-x=5\)
\(\Leftrightarrow x=-5\)
Vậy phương trình có nghiệm x = - 5 .
a, \(3x\left(x-1\right)-x\left(3x-2\right)=5\)
\(\Rightarrow3x^2-3x-\left(3x^2-2x\right)=5\)
\(\Rightarrow3x^2-3x-3x^2+2x=5\)
\(\Rightarrow5x=5\Rightarrow x=1\)
Câu b,c làm tương tự! Cứ tách ra là làm được à!
b ) \(8x\left(2x+1\right)-4x\left(2x-3\right)=-40\)
\(\Leftrightarrow16x^2+8x-8x^2+12x=-40\)
\(\Leftrightarrow20x=-40\)
\(\Leftrightarrow x=-2\)
Vậy phương trình có nghiệm x = - 2
tim so huu ti x biet :
a)\(\left(2x-3\right)^4=\left(2x-3\right)^6\)
b) \(\left(3x+5\right)^3=\left(3x+5\right)^{2016}\)
c) \(\left(2x+1\right)^{2015}=\left(2x+1\right)^{2017}\)
a, (2x-3)4=(2x-3)6
=> (2x-3)6 : (2x-3)4=1
=> (2x-3)3=
=> 2x-3=1
=> 2x=4
=> x=2
b, (3x+5)3=(3x+5)2016
=> (3x+5)2016 : (3x+5)3=1
=> (3x+5)2013=1
=> 3x+5=1
=> 3x=-4
=> x=-4/3
c, (2x+1)2015=(2x+1)2017
=> (2x+1)2017 : (2x+1)2015=1
=> (2x+1)2=1
=> 2x+1=1
=> 2x=0
=> x=0
3, tim x, biet ;
a,\(3x\left[12x-4\right]-9x\left[4x-3\right]=30\)
b,\(x\left[5-2x\right]+2x\left[x-1\right]=15\)
a) \(36x^2-12x-36x^2+27x=30\)
\(15x=30\)
\(x=2\)
b) \(5x-2x^2+2x^2-2x=15\)
\(3x=15\)
\(x=5\)
1)Tim x, biet : a) \(4\left(18-5x\right)-12\left(3x-7\right)=15\left(2x-16\right)-6\left(x+14\right)\)
b) \(2\left(5x-8\right)-3\left(4x-5\right)=4\left(3x-4\right)+11\)
4(18-5x)-12(3x-7)=15(2x-16)-6(x+14)
<=>72-20x-36x+84=30x-240x-6x-84
<=>160x=-86
<=>x=-0.0375
Bai 1. Tim x, y biet
a. \(\left|2-3x\right|=\left|3x+5\right|\)
b. \(\dfrac{x+1}{7}=\dfrac{y-2}{5}\)va 3x-2y=4.
a)|3x-2|=|3x+5|
x<-5/3 or x>=2/3
3x-2=3x+5=> loai
-5/3<=x<2/3
3x-2=-3x-5
6x=-3;x=-1/2(n)
Tim x,biet
\(\left(2x-1\right)^{2012}=\left(2x-1\right)^{2010}\)
\(\left(2x-1\right)^{2012}=\left(2x-1\right)^{2010}\)
\(\Leftrightarrow\left(2x-1\right)^{2012}-\left(2x-1\right)^{2010}=0\)
\(\Leftrightarrow[\left(2x-1\right)^{2010}.\left(2x-1\right)^2]-\left(2x-1\right)^{2010}=0\)\(\Leftrightarrow\left(2x-1\right)^{2010}.[\left(2x-1\right)^2-1]=0\)
\(\Leftrightarrow\left(2x-1\right)^{2010}.[\left(2x-1-1\right)\left(2x-1+1\right)]=0\)
\(\Leftrightarrow\left(2x-1\right)^{2010}.[\left(2x-2\right)2x]=0\)
\(\Leftrightarrow\left[{}\begin{matrix}\left(2x-1\right)^{2010}\\2x\left(2x-2\right)=0\end{matrix}\right.=0\)
\(\Leftrightarrow\left[{}\begin{matrix}2x-1=0\\2x=0\\2x-2=0\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{1}{2}\\x=0\\x=1\end{matrix}\right.\)
Vậy x \(\in\left\{\dfrac{1}{2};0;1\right\}\)
\((2x-1)^{2012} = (2x-1)^{2010} \)
\(\)\(\Leftrightarrow\)\((2x-1)^{2012} - (2x-1)^{2010} = 0\)
\(\Leftrightarrow\)\((2x-1)^{2010} . [(2x-1)^{2} - 1] = 0\)
\(\Leftrightarrow\)\((2x-1)^{2010} . (2x-2).2x = 0\)
\(\Leftrightarrow\)\(4 . (2x-1)^{2010} . (x-1) . x = 0\)
\(\Rightarrow\)\(\left[{}\begin{matrix}\left(2x-1\right)^{2010}=0\\x-1=0\\x=0\end{matrix}\right.\)
\(\Rightarrow\)\(\left[{}\begin{matrix}x=\dfrac{1}{2}\\x=1\\x=0\end{matrix}\right.\)
\(Vậy \) \(x= \)\(\dfrac{1}{2}\); \(x=1\) \(hay\) \(x=0\)
Tim k thuoc N biet, \(x^3y^5+3x^3y^5+.....+\left(2k-1\right)x^3y^5=3249x^3y^5\)
\(x^3y^5+3x^3y^5+...+\left(2k-1\right)x^3y^5=3249x^3y^5\)
\(\Leftrightarrow x^3y^5\left[1+2+3+...+\left(2k-1\right)\right]=3249x^3y^5\)
\(\Leftrightarrow1+3+5+...+\left(2k-1\right)=3249\)
\(\Leftrightarrow\frac{\left[\left(2k-1\right)+1\right].\left(\frac{\left(2k-1\right)-1}{2}+1\right)}{2}=3249\)
\(\Leftrightarrow\frac{2k.\left(k-1+1\right)}{2}=3249\)
\(\Leftrightarrow\frac{2k^2}{2}=3249\)
\(\Leftrightarrow k^2=3249=57^2\) ( ko xét k = - 57 vì theo quy luật thi k luôn dương )
\(\Rightarrow k=57\)
Tim x biet
a/ \(20\left(\frac{x-2}{x+1}\right)^2-5\left(\frac{x+2}{x-1}\right)^2+48\left(\frac{x^2-4}{x^2-1}\right)=0\)
b/ \(\left(2x-1\right)^{2012}=\left(2x-1\right)^{2010}\)
\(b)\) \(\left(2x-1\right)^{2012}=\left(2x-1\right)^{2010}\)
\(\Leftrightarrow\)\(\left(2x-1\right)^{2010}.\left(2x-1\right)^2=\left(2x-1\right)^{2010}\)
\(\Leftrightarrow\)\(\left(2x-1\right)^2=1\)
\(\Leftrightarrow\)\(\orbr{\begin{cases}2x-1=1\\2x-1=-1\end{cases}\Leftrightarrow\orbr{\begin{cases}2x=2\\2x=0\end{cases}}}\)
\(\Leftrightarrow\)\(\orbr{\begin{cases}x=\frac{2}{2}\\x=\frac{0}{2}\end{cases}\Leftrightarrow\orbr{\begin{cases}x=1\\x=0\end{cases}}}\)
Vậy \(x=0\) hoặc \(x=1\)
Chúc bạn học tốt ~
Tim x
a) \(\left(x+3\right)^3-x.\left(3x+1\right)^2+\left(2x+1\right).\left(4x^2-2x+1-3x^2\right)=54\)
b) \(\left(x-3\right)^3-\left(x-3\right).\left(x^2+3x+9\right)+6.\left(x+1\right)^2+3x^2=-33\)
a)(x+3)3-x(3x+1)2+(2x+1)(4x2-2x+1-3x2)=54
\(\Rightarrow\)x3+9x2+27x+27-x(9x2+6x+1)+(2x+1)(x2-2x+1)=54
\(\Rightarrow\)x3+9x2+27x+27-9x3-6x2-x+2x3-4x2+2x+x2-2x+1=54
\(\Rightarrow\)-6x3+26x+28=54
\(\Rightarrow\)-6x3+26x=54-28
\(\Rightarrow\)-6x3+26x=26
\(\Rightarrow\)-6x3+26x-26=0
\(\Rightarrow\)-2(3x3+13x+14)