Tìm X biết
a)22.x-5=32
b)42x-1=64
c)(2.X+2)2=121
d)2x3-1=255
mn ơi giúp mik với mik cần gấp
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\(\left(x-2\right)^5-\left(x-2\right)^3=0\)
\(\Rightarrow\left(x-2\right)^3\left(\left(x-2\right)^2-1\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}x-2=0\\\left(x-2\right)^2-1=0\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=2\\\left(x-2\right)^2=1\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=2\\x-2=1\\x-2=-1\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=2\\x=3\\x=1\end{matrix}\right.\)
Vậy \(x\in\left\{1;2;3\right\}\)
⇒ ( x - 2)3 . (x - 2)2 - (x - 2)3 . 1 = 0 ⇒ ( x - 2)3 . [( x - 2)2 - 1] = 0
\(a,\Leftrightarrow25x^2-70x+49-25x^2=32\\ \Leftrightarrow-70x=-17\Leftrightarrow x=\dfrac{17}{70}\\ b,\Leftrightarrow x^2-6x+9+x^2+2x+1-5=0\\ \Leftrightarrow2x^2-4x+5=0\\ \Leftrightarrow2\left(x^2-2x+1\right)+3=0\\ \Leftrightarrow2\left(x-1\right)^2=-3\Leftrightarrow\left(x-1\right)^2=-\dfrac{3}{2}\left(\text{vô lí}\right)\\ \Leftrightarrow x\in\varnothing\)
a: x/3-1/6=1/5
=>x/3=11/30
hay x=11/90
b: =>1/2x=2
hay x=4
c: =>2/3:x=-7-1/3=-22/3
=>x=-1/11
\(\frac{5}{7}+y\times\frac{1}{2}=\frac{8}{7}:\frac{3}{2}\)
=> \(\frac{5}{7}+y\times\frac{1}{2}=\frac{8}{7}\times\frac{2}{3}\)
=> \(\frac{5}{7}+y\times\frac{1}{2}=\frac{16}{21}\)
=> \(y\times\frac{1}{2}=\frac{16}{21}-\frac{5}{7}=\frac{1}{21}\)
=> \(y=\frac{1}{21}:\frac{1}{2}=\frac{1}{21}\cdot2=\frac{2}{21}\)
5/7 + Y x 1/2 = 8/7 : 3/2
=> 5/7 + Y x 1/2 = 16/21
=> Y x 1/2 = 16/21 - 5/7
=> Y x 1/2 = 1/21
=> Y = 1/21 : 1/2
=> Y = 2/21
Hok tốt ^^
\(a,\Rightarrow2^{2x-5}=2^5\Rightarrow2x-5=5\Rightarrow x=5\\ b,\Rightarrow4^{2x-1}=4^3\Rightarrow2x-1=3\Rightarrow x=2\\ c,\Rightarrow\left[{}\begin{matrix}2x+2=11\\2x+2=-11\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=\dfrac{9}{2}\\x=-\dfrac{13}{2}\end{matrix}\right.\\ d,\Rightarrow2^{x^3}=256=2^8\Rightarrow x^3=8\Rightarrow x=2\)
a)
\(2^{2x-5}=2^5\)
2x-5=5
2x=10
x=5
b)
\(4^{2x-1}=4^3\)
2x-1=3
2x=4
x=2
c)
\(\left(2x+2\right)^2=11^2\)
2x+2=11
2x=9
x=9/2