Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
`#3107.101107`
a)
\(27< 3^x< 243\\ \Rightarrow3^3< 3^x< 3^5\\ \Rightarrow3< x< 5\\ \Rightarrow x=4\)
Vậy, `x = 4`
b)
\(2^x+2^{x+1}+2^{x+2}=56?\\ \Rightarrow2^x+2^x\cdot2+2^x\cdot4=56\\ \Rightarrow2^x\cdot\left(1+2+4\right)=56\\ \Rightarrow2^x\cdot7=56\\ \Rightarrow2^x=8\\ \Rightarrow2^x=2^3\\ \Rightarrow x=3\)
Vậy, `x = 3`
c)
\(3^x+3^{x+2}=810\\ \Rightarrow3^x+3^x\cdot9=810\\ \Rightarrow3^x\cdot\left(1+9\right)=810\\ \Rightarrow3^x\cdot10=810\\ \Rightarrow3^x=81\\ \Rightarrow3^x=3^4\\ \Rightarrow x=4\)
Vậy, `x = 4.`
a) \(27< 3^x< 243\)
\(\Rightarrow3^3< 3^x< 3^5\)
\(\Rightarrow3< x< 5\)
c) \(3^x+3^{x+2}=810\)
\(\Rightarrow3^x\left(1+3^2\right)=810\)
\(\Rightarrow3^x.10=810\)
\(\Rightarrow3^x=810:10\)
\(\Rightarrow3^x=81\)
\(\Rightarrow3^x=3^4\)
\(\Rightarrow x=4\)
(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
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
\(...\Rightarrow3^{x-4}.3^6=2023\)
\(\Rightarrow3^{x-4+6}=3^5\)
\(\Rightarrow3^{x+2}=3^5\Rightarrow x+2=5\Rightarrow x=3\)
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
\(8;a,3^2.\frac{1}{243}.81^2.\frac{1}{3^3}\)
\(=\frac{3^2.\left(3^4\right)^2}{243.3^3}\)
\(=\frac{3^2.3^8}{3^5.3^3}\)
\(=\frac{3^{10}}{3^8}=3^2=9\)
\(b,\frac{4.2^5}{2^3.\frac{1}{16}}\)
\(=\frac{2^2.2^5}{2^3.\frac{1}{2^4}}\)
\(=\frac{2^7}{\frac{1}{2}}=2^7.2=2^8\)
a, \(3^2.\frac{1}{243}.81^2.\frac{1}{3}^3\)
\(=3^2.\frac{1}{243}.\left(3^4\right)^2.\frac{1}{27}\)
\(=3^2.\frac{1}{243}.3^8.\frac{1}{27}\)
\(=\frac{3^2.3^8}{243.27}\)
\(=\frac{3^2.3^8}{3^5.3^3}\)
\(=\frac{3^{10}}{3^8}=3^2=9\)
b, \(\left(4.2^5\right):\left(2^3.\frac{1}{16}\right)\)
\(=\left(2^2.2^5\right):\left(8.\frac{1}{16}\right)\)
\(=2^7:\frac{1}{2}\)
\(=2^8\)
(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
phần b nhé
(X+0,7)3=-27
(X+0,7)3=(-3)3
X+0,7=-3
X=3-0,7=2,3
Vậy...