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đề bài có phải như này không em ?
\(3^{x-4.\left(3^2\right)^3}=243\)
< = > \(3^{x-4.\left(3^2\right)^3}=3^5\)
< = > x - 4 . ( 32 )3 = 5
< = > x - 4 . 729 = 5
< = > x - 2916 = 5
< = > x = 2921
\(...\Rightarrow3^{x-4}.3^6=2023\)
\(\Rightarrow3^{x-4+6}=3^5\)
\(\Rightarrow3^{x+2}=3^5\Rightarrow x+2=5\Rightarrow x=3\)
\(\left(\dfrac{1}{3}\right)^x+\left(\dfrac{1}{3}\right)^{x+3}=\dfrac{28}{243}\\ \Rightarrow\left(\dfrac{1}{3}\right)^x+\left(\dfrac{1}{3}\right)^x.\left(\dfrac{1}{3}\right)^3=\dfrac{28}{243}\\ \Rightarrow\left(\dfrac{1}{3}\right)^x+\left(\dfrac{1}{3}\right)^x.\dfrac{1}{27}=\dfrac{28}{243}\\ \Rightarrow\dfrac{28}{27}\left(\dfrac{1}{3}\right)^x=\dfrac{28}{243}\\ \Rightarrow\left(\dfrac{1}{3}\right)^x=\dfrac{28}{243}:\dfrac{28}{27}\\ \Rightarrow\left(\dfrac{1}{3}\right)^x=\dfrac{1}{9}\\ \Rightarrow\left(\dfrac{1}{3}\right)^x=\left(\dfrac{1}{3}\right)^2\\ \Rightarrow x=2\)
(1/3)x +(1/3)x+3=28/243 (1/3)x +(1/3)x *(1/3)3=28/243 (1/3)x *(1+1/33)=28/243 (1/3)x *28/27=28/243 (1/3)x=1/9 (1/3)x=(1/3)2 vậy x =2
\(\Leftrightarrow\left(\dfrac{1}{3}\right)^x\cdot\dfrac{28}{27}=\dfrac{28}{243}\)
hay x=2
(3^x)^2=1/243.3^3
(3^x)^2=1/9
3x=1/3 hoặc 3x=-1/3
Suy ra x=1/9 hoặc x=-1/9
(3.x)^2 : 3^3=243
9.x^2 : 27=243
9.x^2=243.27
9.x^2=6561
x^2=6561:9
x^2=729
X=27
Bài giải
\(3^x\cdot3^{x+2}=243\)
\(3^{x+x+2}=243\)
\(3^{2x+1}=243\)
\(3^{2x+1}=3^5\)
\(\Rightarrow\text{ }2x+1=5\)
\(2x=5-1\)
\(2x=4\)
\(x=4\text{ : }2\)
\(x=2\)
3^x.3^x+2=243
Suy ra3^x.3^x.3^2=243
3^x.(3^2.1)=243
3^x.9=243
3^x=243:9
3^x=27
Suy ra x=3
3\(x\).3 = 243
3\(x\) = 243 : 3
3\(^x\) = 81
3\(x\) = 34
\(x=4\)
Vậy \(x=4\)
`3^x . 3 = 243`
`=> 3^x = 81`
`=> 3^x = 3^4`
`=> x = 4`
Vậy `x = 4`