tìm x, biết
2x-1/27 = 3/2x-1
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a: =>2x^3=58-4=54
=>x^3=27
=>x=3
b; =>(5-x)^5=2^5
=>5-x=2
=>x=3
c: =>(5x-6)^3=4^3
=>5x-6=4
=>5x=10
=>x=2
d: (3x)^3=(2x+1)^3
=>3x=2x+1
=>x=1
1=>2x3=54
=>x3=27 =>x=3
2=>(5-x)5=25
=>5-x=2
=>x=3
3=>(5x-6)3=43
=>5x-6=4
=>5x=10=>x=2
4=>3x=2x+1
=>x=1
\(2x-10,01=19,01-3\\ \Rightarrow2x-10,01=16,01\\ \Rightarrow2x=16,01+10,01\\ \Leftrightarrow2x=26,02\\ \Leftrightarrow x=26,02:2=13,01\)
2x-10,01=19,01-3
=> 2x-10,01= 16,01
=> 2x= 16,01+10,01
=>2x= 26,02
=> x= 26,02: 2= 13,01
a/\(x:27=3,6\)
\(\Rightarrow x=97,2\)
b/\(\dfrac{2x+1}{-27}=\dfrac{-3}{2x+1}\)
\(\Rightarrow\left(2x+1\right)^2=81\)
\(\Rightarrow\left[{}\begin{matrix}2x+1=9\\2x+1=-9\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}2x=8\\2x=-10\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=4\\x=-5\end{matrix}\right.\)
Vậy \(x\in\left\{4;-5\right\}\)
Lời giải:
a.
$x:27=-2:3,6=\frac{-5}{9}$
$x=27.\frac{-5}{9}=-15$
b.
$\frac{2x+1}{-27}=\frac{-3}{2x+1}$
$\Rightarrow (2x+1)^2=(-27)(-3)=81=9^2=(-9)^2$
$\Rightarrow 2x+1=9$ hoặc $2x+1=-9$
$\Rightarrow x=4$ hoặc $x=-5$
a) 4(x + 3)(3x - 2) - 3(x - 1)(4x - 1) = -27
<=> 4(3x2 + 7x - 6) - 3(4x2 - 5x + 1) = -27
<=> 12x2 + 28x - 24 - 12x2 + 15x - 3 = -27
<=> 43x = 0 <=> x = 0
Vậy nghiệm là x = 0
b) Đề không rõ, mình sửa lại đề nha:
4x(2x2 - 1) + 27 = (4x2 + 6x + 9)(2x + 3)
<=> 8x3 - 4x + 27 = 8x3 + 24x2 + 36x + 27
<=> 24x2 + 40x = 0 <=> x = 0 hay x = -5/3
Vậy nghiệm là x = 0 hay x = -5/3
\(\dfrac{1}{27}+\left(2x-\dfrac{1}{3}\right)^3=\dfrac{1}{3}\\ \Leftrightarrow\left(2x-\dfrac{1}{3}\right)^3=\dfrac{1}{3}-\dfrac{1}{27}=\dfrac{8}{27}=\left(\dfrac{2}{3}\right)^3\\ \Leftrightarrow2x-\dfrac{1}{3}=\dfrac{2}{3}\Leftrightarrow2x=1\Leftrightarrow x=\dfrac{1}{2}\)
\(\dfrac{1}{27}\)+\(\left(2x-\dfrac{1}{3}\right)^3\)=\(\dfrac{1}{3}\)
⇔\(\left(2x-\dfrac{1}{3}\right)^3\)=\(\dfrac{1}{3}\)−\(\dfrac{1}{27}\)=\(\dfrac{8}{27}\)=\(\left(\dfrac{2}{3}\right)^3\)
⇔\(2x-\dfrac{1}{3}\)=\(\dfrac{2}{3}\)
⇔2\(x\)=1⇔\(x\)=\(\dfrac{1}{2}\)
Vậy \(x\)=\(\dfrac{1}{2}\)
a) \(3\left(2x-5\right)+125=134\)
\(\Leftrightarrow3\left(2x-5\right)=9\)
\(\Leftrightarrow2x-5=3\)
\(\Leftrightarrow2x=8\Leftrightarrow x=4\)
b) \(\left(2x+5\right)+\left(2x+3\right)+\left(2x+1\right)=27\)
\(\Leftrightarrow6x+9=27\)
\(\Leftrightarrow6x=18\Leftrightarrow x=3\)
d) \(27\left(x-27\right)-27=0\)
\(\Leftrightarrow27\left(x-27\right)=27\)
\(\Leftrightarrow x-27=1\Leftrightarrow x=28\)
\(\frac{2x-1}{3}=\frac{27}{2x-1}\)
\(\Rightarrow\left(2x-1\right)\left(2x-1\right)=27\cdot3\)
\(\Rightarrow\left(2x-1\right)^2=81\)
\(\Rightarrow\left(2x-1\right)^2=\left(\pm9\right)^2\)
\(\Rightarrow\orbr{\begin{cases}2x-1=9\\2x-1=-9\end{cases}}\)
\(\Rightarrow\orbr{\begin{cases}2x=10\\2x=-8\end{cases}}\)
\(\Rightarrow\orbr{\begin{cases}x=5\\x=-4\end{cases}}\)
ko bt đề đúng ý bn chưa ?
\(\frac{2x-1}{3}=\frac{27}{2x-1}\)
\(\Leftrightarrow\left(2x-1\right)^2=27.3=81\)
\(\Leftrightarrow\orbr{\begin{cases}2x-1=9\\2x-1=-9\end{cases}\Leftrightarrow\orbr{\begin{cases}2x=10\\2x=-8\end{cases}\Leftrightarrow}\orbr{\begin{cases}x=5\\x=-4\end{cases}}}\)
2x-\(\frac{1}{27}\)=\(\frac{3}{2}\)x-1
<=>2x-\(\frac{3}{2}\)x=\(\frac{1}{27}\)-1
<=>\(\frac{1}{2}\)x=\(\frac{-26}{27}\)
<=>x=\(\frac{-26}{27}\):\(\frac{1}{2}\)
<=>x=\(\frac{-52}{27}\)
Vậy x=\(\frac{-52}{27}\)