3. ( 2x-1)^4=243
a) 3^2x-1=243
b) 3^x+1=9^x
c) (4/7-1/2x)^3=-8/34
a,\(3^2x-1=243\)
\(9x-1=243\)
\(9x=244\)
\(x=\frac{244}{9}\)
b,\(3^x+1=3^{2x}\)
\(x+1=2x\)
\(x-2x=-1\)
\(-1x=-1\)
\(x=1\)
Mình chỉ làm được 2 câu thôi chúc cậu học tốt!
a) \(3^{2x-1}=243\)
\(\Rightarrow3^{2x-1}=3^5\)
\(\Rightarrow2x-1=5\)
\(\Rightarrow2x=5+1\)
\(\Rightarrow2x=6\)
\(\Rightarrow x=6:2\)
\(\Rightarrow x=3\)
Vậy \(x=3.\)
b) \(3^{x+1}=9^x\)
Vậy \(x=1.\)
c) \(\left(\frac{4}{7}-\frac{1}{2}x\right)^3=-\frac{8}{34}\)
Câu này hình như đề bài sai, bạn xem lại nhé.
Chúc bạn học tốt!
a) 32x-1= 243 b) (3x)2 :33= 1/243
c) 23x+2= 4x+5 d) 3x+1= 9x
a) \(3^{2x-1}=243\)
\(\Leftrightarrow3^{2x-1}=3^5\)
\(\Leftrightarrow2x-1=5\)
\(\Leftrightarrow2x=5+1\)
\(\Leftrightarrow2x=6\)
\(\Leftrightarrow x=\dfrac{6}{2}\)
\(\Leftrightarrow x=3\)
Vậy \(x=3\)
b) \(\left(3^x\right)^2:3^3=\dfrac{1}{243}\)
\(\Leftrightarrow3^{2x}:3^3=\dfrac{1}{3^5}\)
\(\Leftrightarrow3^{2x}:3^3=3^{-5}\)
\(\Leftrightarrow3^{2x-3}=3^{-5}\)
\(\Leftrightarrow2x-3=-5\)
\(\Leftrightarrow2x=-5+3\)
\(\Leftrightarrow2x=-2\)
\(\Leftrightarrow x=-\dfrac{2}{2}\)
\(\Leftrightarrow x=1\)
Vậy \(x=1\)
c) \(2^{3x+2}=4^{x+5}\)
\(\Leftrightarrow2^{3x+2}=\left(2^2\right)^{x+5}\)
\(\Leftrightarrow2^{3x+2}=2^{2\left(x+5\right)}\)
\(\Leftrightarrow3x+2=2\left(x+5\right)\)
\(\Leftrightarrow3x+2=2x+10\)
\(\Leftrightarrow3x-2x=10-2\)
\(\Leftrightarrow x=8\)
Vậy \(x=8\)
d) \(3^{x+1}=9^x\)
\(\Leftrightarrow3^{x+1}=\left(3^2\right)^x\)
\(\Leftrightarrow3^{x+1}=3^{2x}\)
\(\Leftrightarrow x+1=2x\)
\(\Leftrightarrow2x-x=1\)
\(\Leftrightarrow x=1\)
Vậy \(x=1\)
( x - 2 )^2= 1
(2x - 1)^3 = -8
(x - 1)^x+2 = (x - 1)^x+4
(2x-3)^5 = -243
1) \(\left(x-2\right)^2=1\)
\(\Leftrightarrow\left(x-2\right)^2=1^2\)
\(\Leftrightarrow\orbr{\begin{cases}x-2=1\\x-2=-1\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=3\\x=1\end{cases}}\)
\(\Rightarrow\orbr{\begin{cases}x=3\\x=1\end{cases}}\)
2) \(\left(2x-1\right)^3=-8\)
\(\Leftrightarrow\left(2x-1\right)^3=\left(-2\right)^3\)
\(\Leftrightarrow2x-1=-2\)
\(\Leftrightarrow2x=-2+1\)
\(\Leftrightarrow2x=-1\)
\(\Rightarrow x=-\frac{1}{2}\)
3) \(\left(x-1\right)^{x+2}=\left(x-1\right)^{x+4}\)
\(\Leftrightarrow x+2=x+4\)
\(\Leftrightarrow2=4\)
\(\Rightarrow x\in\varnothing\)
4) \(\left(2x-3\right)^5=-243\)
\(\Leftrightarrow\left(2x-3\right)^5=\left(-3\right)^5\)
\(\Leftrightarrow2x-3=-3\)
\(\Leftrightarrow2x=-3+3\)
\(\Leftrightarrow2x=0\)
\(\Rightarrow x=0\)
\(\left(x-2\right)^2=1\)
\(=>\left(x-2\right).\left(x-2\right)=1\)
\(+TH1\)\(\left(x-2\right)=1\)
\(=>1.1=1\left(TM\right)\)
\(+TH2\)\(\left(x-2\right)=-1\)
\(=>\left(-1\right).\left(-1\right)=1\left(TM\right)\)
\(=>x=1;-1\)
1,3^2x-1=243
3^x+1=9
2^3x+2=4^x+5
A.3^x=243 B.4^x=4096 C. 5^3-x=25 D.8^2x-3=512 E.2214-5.7^2x-3=499 J. 2^x+3+2^x+1=80
a: 3^x=243
=>3^x=3^5
=>x=5
b: 4^x=4096
=>4^x=4^5
=>x=5
c: 5^3-x=25
=>3-x=2
=>x=1
d: =>2x-3=3
=>2x=6
=>x=3
j: =>2^x*8+2^x*2=80
=>2^x=8
=>x=3
Tìm x, biết:
a) \(\dfrac{x}{3}\) - 5 = \(\dfrac{2x}{5}\)
b) 4 + 3x = 8 - x
c) 2 . 3\(^{x+1}\) - 5 . 3\(^x\) = 243
a: =>1/3x-2/5x=5
=>-1/15x=5
=>x=-75
b: =>4x=4
=>x=1
c: =>6*3^x-5*3^x=243
=>3^x=243
=>x=5
( x - 2 )^2= 1
(2x - 1)^3 = -8
(x - 1)^x+2 = (x - 1)^x+4
(2x-3)^5 = -243
\(\left(x-2\right)^2=1\)
=> \(\left(x-2\right)^2=1^2\)
=> \(\left(x-2\right)^2=\left(-1\right)^2\)
=> \(\left[{}\begin{matrix}x-2=1\\x-2=-1\end{matrix}\right.\) => \(\left[{}\begin{matrix}x=1+2\\x=\left(-1\right)+2\end{matrix}\right.\)
=> \(\left[{}\begin{matrix}x=3\\x=1\end{matrix}\right.\)
Vậy \(x\in\left\{3;1\right\}.\)
\(\left(2x-1\right)^3=-8\)
=> \(\left(2x-1\right)^3=\left(-2\right)^3\)
=> \(2x-1=-2\)
=> \(2x=\left(-2\right)+1\)
=> \(2x=-1\)
=> \(x=\left(-1\right):2\)
=> \(x=-\frac{1}{2}\)
Vậy \(x=-\frac{1}{2}.\)
\(\left(2x-3\right)^5=-243\)
=> \(\left(2x-3\right)^5=\left(-3\right)^5\)
=> \(2x-3=-3\)
=> \(2x=\left(-3\right)+3\)
=> \(2x=0\)
=> \(x=0:2\)
=> \(x=0\)
Vậy \(x=0.\)
Chúc bạn học tốt!
a) (x - 2)2 = 1
=> x - 2 = 1 hoặc x - 2 = -1
x = 3 ; x = 1
Vậy x = 3; x = 1
b) (2x - 1)3 = -8
=> 2x - 1 = -2
2x = -1
x = \(\frac{-1}{2}\)
Vậy x = \(\frac{-1}{2}\)
c) (2x - 3)5 = -243
=> (2x - 3)5 = (-3)5
=> 2x - 3 = -3
2x = 0
x = 0
Vậy x = 0
Tìm x biết: \(\frac{1}{3}.\left(2x-\frac{1}{2}\right)^4=\frac{1}{243}\)
\(\frac{1}{3}\left(2x-\frac{1}{2}\right)^4=\frac{1}{243}\)
=> \(\left(2x-\frac{1}{2}\right)^4=\frac{1}{243}:\frac{1}{3}=\frac{1}{243}\cdot3=\frac{1}{81}\)
=> \(\left(2x-\frac{1}{2}\right)^4=\left(\pm\frac{1}{3}\right)^4\)
=> \(\hept{\begin{cases}2x-\frac{1}{2}=\frac{1}{3}\\2x-\frac{1}{2}=-\frac{1}{3}\end{cases}}\Rightarrow\hept{\begin{cases}x=\frac{5}{12}\\x=\frac{1}{12}\end{cases}}\)
(2x-1/2)^4=1/243:1/3
(2x-1/2)=1/243×3/1
(2x-1/2)^4=1/81
(2x-1/2)^4=1/3^4
(2x-1/2)=1/3
2x=1/3+1/2
2x=5/6
x=5/6:2/1
x=5/6×1/2
x=5/12
Bài 1: Tìm x biết
a) | 4 - x | + 2x = 3
b) ( x - 1 )^5 = -243
a: =>|x-4|=3-2x
\(\Leftrightarrow\left\{{}\begin{matrix}x< =\dfrac{3}{2}\\\left(3-2x-x+4\right)\left(3-2x+x-4\right)=0\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}x< =\dfrac{3}{2}\\\left(-3x+7\right)\left(-x-1\right)=0\end{matrix}\right.\Leftrightarrow x=-1\)
b: =>x-1=-3
=>x=-2
tìm x
a.2^3+2=4^X+5
b.3^x+1=9^x
c.3^2x-1=243
a, 23 + 2 = 4x + 5
8 + 2 = 4x + 5
10 = 4x + 5
=> 4x = 5
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