a

\(5\frac{4}{7}:x+=13\)

\(\frac{39}{7}:x=13\)

\(x=\frac{39}{7}:13\)

\(x=\frac{3}{7}\)

\(\frac{4}{7}x=\frac{9}{8}-0,125\)

\(\frac{4}{7}x=1\)

\(x=1:\frac{4}{7}\)

\(x=\frac{7}{4}=1\frac{3}{4}\)

Khó quá

Tìm x

\(5^2.x-2^4.x=3^4-6.3^2\)

\(25x-16x=81-6.9\)

\(x\left(25-16\right)=81-54\)

\(x.9=27\)

\(x=27\div9\)

\(x=3\)

Vậy \(x=3\).

Ta có:

\(\frac{1}{2}\cdot2^n+4\cdot2^n=9\cdot5^n\)

\(2^n\left(\frac{1}{2}+4\right)=9\cdot5^n\)

\(\frac{9}{2}\cdot2^n=9\cdot5^n\)

Tức: \(9\cdot\frac{1}{2}\cdot2^n=9\cdot5^n\)

Suy ra: \(2^{n-1}=5^n\)

Nhận thấy: \(n-1< n\)

Hơn nữa \(2< 5\)

Do đó: \(2^{n-1}< 5^n\)

Vậy không có n thỏa mãn

kết quả bằng 9/5 đó bạn

giải ra các cách được hông bạn

\(\left(5^{2x}\cdot5^{x+2}\right):25=125^2\)   

\(5^{2x+x+2}=125^2\cdot25\)   

\(5^{3x+2}=\left(5^3\right)^2\cdot5^2\)   

\(5^{3x+2}=5^6\cdot5^2\)   

\(5^{3x+2}=5^8\)   

\(\Rightarrow3x+2=8\)   

\(3x=8-2\)   

\(3x=6\)   

\(x=6:3\)   

\(x=2\)

\(\frac{1}{2}x+\frac{3}{5}x=-\frac{2}{5}\\ x\left(\frac{1}{2}+\frac{3}{5}\right)=-\frac{2}{5}\\ x.\frac{11}{10}=-\frac{2}{5}\\ x=-\frac{4}{11}\)

\(\frac{1}{2}x+\frac{3}{5}x=\frac{-2}{5}\)

\(\left(\frac{1}{2}+\frac{3}{5}\right)x=\frac{-2}{5}\)

\(\frac{11}{10}x=\frac{-2}{5}\)

\(x=\frac{-2}{5}:\frac{11}{10}\)

\(x=-\frac{4}{11}\)

a) 2^x . 4 = 128

2^x = 128 : 4

2^x = 32

2^x = 2⁵

=> x = 5

b) 2^x . 2⁴ = 2⁶

=> x + 4 = 6

x = 6 - 4

x = 2

c) 5x + x = 39 - 3¹¹ : 3⁹

6x = 39 - 3²

6x = 39 - 9

6x = 30

x = 30 : 6

x = 5

d) 9^{x - 1} = 81

9^{x - 1} = 9²

=> x - 1 = 2

x = 2 + 1

x = 3

e) 6x = 5²¹ : 5¹⁹ + 3 . 2² - 7⁰

6x = 5² + 3 . 4 - 1

6x = 25 + 12 - 1

6x = 37 - 1

6x = 36

x = 36 : 6

x = 6

\(a)\frac{2}{3}x-\frac{1}{2}=\frac{5}{12}\)

\(\Rightarrow\frac{2}{3}x=\frac{5}{12}+\frac{1}{2}=\frac{11}{12}\)

\(\Rightarrow x=\frac{11}{12}:\frac{2}{3}=\frac{11}{8}\)

\(b)\left(2\frac{4}{5}x-50\right):\frac{2}{3}=51\)

\(\Rightarrow\frac{14}{5}x-50=51.\frac{2}{3}=34\)

\(\Rightarrow\frac{14}{5}x=34+50=84\)

\(\Rightarrow x=84:\frac{14}{5}=30\)

a) 2/3.x - 1/2 = 5/12

            2/3.x = 5/12 + 1/2

            2/3.x = 11/12

                  x = 11/12 : 2/3

                   x = 11/8

b) \(\left(2\frac{4}{5}.x-50\right):\frac{2}{3}=51\)

                  \(\frac{14}{5}.x-50=51.\frac{2}{3}\)

                   \(\frac{14}{5}.x-50=34\)

                                \(\frac{14}{5}.x=34+50\)

                                \(\frac{14}{5}.x=84\)

                                         \(x=84:\frac{14}{5}\)

                                         \(x=30\)

\(\frac{1}{2}\cdot2^x+2^x\cdot2^2=2^8+2^5\)

\(2^x\left(\frac{1}{2}+4\right)=2^8+2^5\)

\(2^x\cdot\frac{9}{2}=288\)

\(2^x=64\)

\(2^x=2^6\)

\(x=6\)

\(9^x:3^x=3^7\)

\(3^{2x}:3^x=3^7\)

\(3^x=3^7\)

\(x=7\)

\(7^{x+2}+2\cdot7^{x-1}=345\)

\(7^x\cdot7^2+2\cdot7^x:7=345\)

\(7^x\left(7^2+\frac{2}{7}\right)=345\)

\(7^x\cdot\frac{345}{7}=345\)

\(7^x=7\)

\(x=1\)

a) 1/2.2^x + 2^x+2 = 256 + 32

1/2.2^x + 2^2.2^x=288

2^x(1/2+4)= 288

2^x.4,5=288

2^x= 288:4,5

2^x=64=2^6

x=6

320 : ( x - 1 ) = ( 5³ - 5² ) : 4 + 15

<=> 320 : ( x - 1 ) = ( 125 - 25 ) : 4 + 15

<=> 320 : ( x - 1 ) = 100 : 4 + 15

<=> 320 : ( x - 1 ) = 40

<=> x - 1 = 8

<=> x = 9

240 : ( x - 5 ) = 2² . 5² - 20

<=> 240 : ( x - 5 ) = 4 . 25 - 20

<=> 240 : ( x - 5 ) = 80

<=> x - 5 = 3

<=> x = 8

70 : ( x - 3 ) = ( 3⁴ - 1 ) : 4 - 16

<=> 70 : ( x - 3 ) = 80 : 4 - 16

<=> 70 : ( x - 3 ) = 4

<=> x - 3 = 35/2

<=> x = 41/2

a) 320: (x-1) = (5³ - 5²):4 + 15         b) 240: (x-5) = 2².5² - 20      c) 70:(x-3) = (3⁴ - 1):4 - 16

    320: (x-1) = (125- 25): 4 + 15          240: (x-5) = 4.25 - 20            70:(x-3) = (81-1): 4 - 16

    320: (x-1) = 100:4 + 15                   240: (x-5) = 100 - 20              70: (x-3) = 80: 4 - 16

    320: (x-1) = 25 + 15                        240: (x-5) = 80                       70: (x-3) = 20  -16

    320: (x-1) = 40                                (x-5) = 240:80                        70: (x-3) = 4

    (x-1) = 320:40                                 (x-5) = 3                                 (x-3) = 70:4 

      (x-1) = 80                                      x = 5+3                                   (x-3) = 17,5

      x = 80+1                                        x = 8                                       x = 17,5 : 3

       x = 81                                                                                          x = 5,83