\(7^{2x}+7^{2x+2}=2450\)

\(\Rightarrow7^{2x}\left(1+7^2\right)=2450\)

\(\Rightarrow7^{2x}\cdot50=2450\)

\(\Rightarrow7^{2x}=49=7^2\)

\(\Rightarrow2x=2\Rightarrow x=1\)

7^2x(1+ 49) = 2450

7^2x = 2450/50 = 49 = 7²

2x = 2

x = 1

không có x vì 7²⁺7²⁺²⁼2450

\(7^{2x}+7^{2x+2}=2450\)

\(7^{2x}\left(1+7^2\right)=2450\)

\(7^{2x}=2450\div50\)

\(7^{2x}=49\)

\(\Rightarrow2x=2\)

\(\Leftrightarrow x=1\)

\(7^{2x}+7^{2x+2}=2450\)

\(\Leftrightarrow7^{2x}+7^{2x}.7^2=2450\)

\(\Leftrightarrow7^{2x}\left(1+7^2\right)=2450\)

\(\Leftrightarrow49^x\left(1+49\right)=2450\)

\(\Leftrightarrow49^x.50=2450\)

\(\Leftrightarrow49^x=2450:50\)

\(\Leftrightarrow49^x=49\)

\(\Rightarrow x=1\)

vậy x=1

a) \(\left(2x+1\right)\left(x-\frac{1}{7}\right)=0\Leftrightarrow\orbr{\begin{cases}2x+1=0\\x-\frac{1}{7}=0\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=-\frac{1}{2}\\x=\frac{1}{7}\end{cases}}.\)

Vậy.....

b) \(7^{2x}+7^{2x+2}=2450\Leftrightarrow7^{2x}\left(1+7^2\right)=2450\Leftrightarrow7^{2x}\cdot50=2450\Leftrightarrow7^{2x}=49\Leftrightarrow2x=2\Leftrightarrow x=1.\)

Vậy....

Học tốt nhé ^3^

a) 2^x+2^x+3=144

2^x . 1 + 2^x . 2³ = 144

2^x . ( 1 + 2³ ) = 144

2^x . 9 = 144

2^x = 144 : 9

2^x = 16

2^x = 2⁴

=> x = 4

b) 7^2x + 7^2x+2 = 2450

7^2x . 1 + 7^2x . 7²= 2450

7^2x . ( 1 + 7² ) = 2450

7^2x . 50 = 2450

7^2x = 2450 : 50

7^2x = 49

7^2x = 7²

=> 2x = 2

=> x = 1

Ta có : 2^x + 2^{x + 3} = 144

=> 2^x (1 + 2³) = 144

=> 2^x . 9 = 144

=> 2^x = 144 : 9

=> 2^x = 16

=> 2^x = 2⁴

=> x = 4 

\(7^{2x}+7^{2x+2}=2450\)

\(7^{2x}+7^{2x}\cdot7^2=2450\)

\(7^{2x}\cdot\left(1+49\right)=2450\)

\(7^{2x}=2450:50=49\)

\(7^{2x}=7^2\)

\(2x=2\)

\(x=1\)

TL:

 \(x=1\)

*Hok tốt

a) Ta có \(\frac{x-2}{2}=\frac{-4}{\left(x-2\right)^2}\)

=> (x - 2)³ = -8

=> x - 2 = -2

=> x = 0

Vậy x = 0

b) Ta có 7^2x + 7^{2x + 2} = 2450

=> 7^2x(1 + 7²) = 2450

=> (7²)^x.50 = 2450

=> 49^x = 49

=> x = 1

Vậy x = 1

7^2x+7^2x+2=2450

7^2x+7^2x.7²=2450

7^2x.(1+7²)=2450

7^2x.50=2450

7^2x     =2450:50

7^2x    =49

7^2x    =7^2.1

=>x=1

Chuc bn hoc tot