\(3^x+3^{x+1}+3^{x+2}=243.39\)

\(3^x.\left(1+3^1+3^2\right)=243.3.13\)

\(3^x.\left(1+3+9\right)=\left(243.3\right).13\)

\(3^x.13=729.13\)

\(3^x=729.13\div13\)

\(3^x=729\)

\(3^x=3^6\)

\(x=6\)

\(3^x+3^{x+1}+3^{x+2}=243.39\)

\(\Leftrightarrow3^x+3^x.3+3^x.3^2=9477\)

\(\Leftrightarrow3^x\left(1+3+3^2\right)=9477\)

\(\Leftrightarrow3^x.13=9477\)

\(\Leftrightarrow3^x=9477:13\)

\(\Leftrightarrow3^x=729\)

\(\Leftrightarrow3^x=3^6\)

\(\Leftrightarrow x=6\)

~ Rất vui vì giúp đc bn ~

\(3^x+3^{x+1}+3^{x+2}=243\cdot39\)

\(\Leftrightarrow3^x\left(1+3+3^2\right)=3^5\cdot3\cdot13\)

\(\Leftrightarrow3^x\cdot13=3^6\cdot13\)

\(\Leftrightarrow3^x=3^6\Rightarrow x=6\)

+) x³ : 2 = 4

x³ = 4 . 2 = 8

x³ = 2³

=> x = 2

+) 5^x-2 = 1

=> 5^x : 5² = 1

=> 5^x = 5²

=> x = 2

+) 3^x + 3^x+1 + 3^x+2 = 243 . 39

3^x + 3^x . 3 + 3^x . 3² = 9477

3^x . (1+3+ 3²) = 9477

3^x . 13 = 9477

3^x = \(\frac{9477}{13}\) = 729

3^x = 3⁶

=> x = 6

x³:2=4

\(\Rightarrow\)x³=4.2

\(\Rightarrow\)x³=8

\(\Rightarrow\)x³=2³

^{\(\Rightarrow\)}x=2

Vậy:x=2

5^x-2=1

\(\Rightarrow\)5^x-2=5⁰

\(\Rightarrow\)x-2=0

\(\Rightarrow\)x=2

Vậy:x=2

3^x+3^x+1+3^x+2=243.39

\(\Rightarrow\)3^x+3^x+1+3^x+2=9477

\(\Rightarrow\)3^x+3^x.3+3^x.3²=9477

\(\Rightarrow\)3^x=9477:13

\(\Rightarrow\)3^x=729

\(\Rightarrow\)3^x=3⁶

^{\(\Rightarrow\)}x=6

Vậy:x=6

+) \(x^3\):2=4

\(\Rightarrow\)\(x^3\)=4.2

\(\Rightarrow\)\(x^3\)=8

\(\Rightarrow\)\(x^3\)= \(2^3\)

\(\Rightarrow\)\(x\) = 2

Vậy x=2

+) \(5^{x-2}\)=1

\(\Rightarrow\) \(5^{x-2}\)=\(5^0\)

\(\Rightarrow x-2=0\)

\(\Rightarrow x=0+2\)

\(\Rightarrow x=2\)

Vậy x=2

+) \(3^x+3^{x+1}+3^{x+2}=143.39\)

\(\Rightarrow\)\(3^x+3^{x+1}+3^{x+2}=9477\)

\(\Rightarrow\)\(3^x+3^x.3+3^x.9=9477\)

\(\Rightarrow3^x=9477:13\)

\(\Rightarrow3^x=729\)

\(\Rightarrow3^x=3^6\)

\(\Rightarrow x=6\)

Vậy x=6

3^x + 3^x+1 + 3^x+2 = 243 . 39

3^x.(1+3+9) = 3⁶ . 13

3^x . 13 = 3⁶ . 13

=> x = 13

a. 3^x=1-x^2

x=0 la nghiem

x>=1;  VT>=3 VP<=0 vo nghiem 

b. (de bai thieu n khac 0 vi neu n=0 dung voi moi x)

3x-14=1=> x=5

c.(5^2x5^^x+1)=5^4

5^{^x+1}=5^2=> x=1

1999^2x-6 = 1

2x-  6 = 0

x = 3

mình ko hiểu

đề bài cho lắm bn

ạ vì mình mới lên 

lớp 6 thôi bnaj

mk cx vừa nên lớp 6 mà đi hc đợi tuyển f lm nên mk hỏi z thoy nếu bạn  k lm dc cx k sao

đề bài sai r bn ơi

 20 . 2^x + 1 = 10.4^2 + 1 

 20 . 2^x + 1 = 10 . 16 + 1

20 . 2^x + 1 = 161

20 . 2^x = 161 - 1

20 . 2^x = 160

2^x = 8

2^x = 2^3

=> x = 3

Ban co giai dc phan 2 ko ?

( 4 - x : 2 )^3 - 1 = 2 . ( 2^3 - 5 : 2^0 )

( 4 - x : 2 )^3 - 1 = 2 . ( 8 - 5 : 1 )

( 4 - x : 2 )^3 - 1 = 2 . 3

( 4 - x : 2 )^3 - 1 = 6

( 4 - x : 2 )^3  = 7

=> ko tìm đc x