![](https://rs.olm.vn/images/avt/0.png?1311)
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
a)
3x+1+3x+1.32=810
3x+1(1+9)=810
3x+1.10=810
3x+1=81
3x+1=34
x+1=4
=>x=3
b) 3x+3x+2=810
3x+3x.32=810
3x(1+9)=810
3x=81=34
=>x=4
![](https://rs.olm.vn/images/avt/0.png?1311)
3ˣ⁺¹ + 3ˣ⁺³ = 810
3ˣ⁺¹.(1 + 3²) = 810
3ˣ⁺¹.10 = 810
3ˣ⁺¹ = 810 : 10
3ˣ⁺¹ = 81
3ˣ⁺¹ = 3⁴
x + 1 = 4
x = 4 - 1
x = 3
![](https://rs.olm.vn/images/avt/0.png?1311)
\(1,\Leftrightarrow3^x\left(1+3^2\right)=810\\ \Leftrightarrow3^x=\dfrac{810}{10}=81=3^4\\ \Leftrightarrow x=4\\ 2,\Leftrightarrow\left[{}\begin{matrix}\dfrac{2}{3}x=1\\0,4x=-5\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{3}{2}\\x=-\dfrac{25}{2}\end{matrix}\right.\)
![](https://rs.olm.vn/images/avt/0.png?1311)
c) 3x + 4 + 3x + 2 = 810
=> 3x . 34 + 3x . 32 = 810
=> 3x.(34 + 32) = 810
=> 3x . (81 + 9) = 810
=> 3x . 90 = 810
=> 3x = 810 : 90
=> 3x = 9
=> 3x = 32
=> x = 2
d) 3x + 3x + 2 = 810
=> 3x + 3x . 32 = 810
=> 3x . (1 + 32) = 810
=> 3x . (1 + 9) = 810
=> 3x . 10 = 810
=> 3x = 810 : 10
=> 3x = 81
=> 3x = 34
=> x = 4
c, \(3^{x+4}+3^{x+2}=810\)
\(\Leftrightarrow3^x\left(3^4+3^2\right)=810\)
\(\Leftrightarrow3^x.90=810\)
\(\Leftrightarrow3^x=9=3^2\)
\(\Leftrightarrow x=2\)
d, \(3^x+3^{x+2}=810\)
\(\Leftrightarrow3^x\left(1+3^2\right)=810\)
\(\Leftrightarrow3^x.10=810\)
\(\Leftrightarrow3^x=81=3^4\)
\(\Leftrightarrow x=4\)
P/s: Toán thường thôi nhỉ :) Ko nâng cao lắm
![](https://rs.olm.vn/images/avt/0.png?1311)
Ta có:
\(3^{x+1}+3^{x+3}=810\)
\(3^xx3^1+3^xx3^3=810\)
\(3^xx\left(3+27\right)=810\)
\(3^xx30=810\)
\(3^x=810:30=27\)
\(3^x=3^3\)
\(\Rightarrow x=3\)
3x+1+3x+3=810
=>3x.3+3x.33=810
=>3x.(3+33)=810
=>3x.30=810
=>3x=810:30
=>3x=27=33
=>x=3
Chúc bạn học giỏi nha ^-^!!!
![](https://rs.olm.vn/images/avt/0.png?1311)
`#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) \(3^x+3^{x+2}=810\)
\(\Rightarrow3^x\left(1+3^2\right)=810\)
\(\Rightarrow3^x.10=810\)
\(\Rightarrow3^x=810:10\)
\(\Rightarrow3^x=81\)
\(\Rightarrow3^x=3^4\)
\(\Rightarrow x=4\)
![](https://rs.olm.vn/images/avt/0.png?1311)
\(3^x+3^{x+2}=810\)
\(\Rightarrow3^x\left(1+3^2\right)=810\Rightarrow3^x.10=810\)
\(\Rightarrow3^x=81\Rightarrow x=4\)
\(3^{x+1}+3^{x+3}=810\\ 3^{x+1}\left(1+3^2\right)=810\\ 3^{x+1}\cdot10=810\\ 3^{x+1}=81\\ 3^{x+1}=3^4\\ x+1=4\\ x=3\)
Ta có:
\(3^{x+1}+3^{x+3}=810\)
\(\Rightarrow3^{x+1}.1+3^{x+1}.3^2=810\)
\(\Rightarrow3^{x+1}.\left(1+3^2\right)=810\)
\(\Rightarrow3^{x+1}.10=810\)
\(\Rightarrow3^{x+1}=810:10=81=3^4\)
\(\Rightarrow x+1=4\)
\(\Rightarrow x=3\)