K
Khách

Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.

4 tháng 9 2015

a. => (1/3.x):2/3=7/4:2/5

=> 1/3.x=(7/4.2/3):2/5

=> 1/3.x=7/6.5/2

=> 1/3.x=35/12

=> x=35/12:1/3

=> x=35/12.3

=> x=35/4

b. => 4,5.(0,1.x)=0,3.2,25

=> 4,5.(0,1.x)=0,675

=> 0,1.x=0,675:4,5

=> 0,1.x=0,15

=> x=0,15:0,1

=> x=1,5

c. => 2.(1/4.x)=8.0,02

=> 1/2.x=0,16

=> x=0,16:1/2

=> x=0,16.2

=> x=0,32

d. => 3:9/4=3/4:(6.x)

=> 3.(6.x)=9/4.3/4

=> 18.x=27/16

=> x=27/16:18

=> x=27/16.1/18

=> x=3/32

17 tháng 7 2017

a) ( 1/3 . x ) : 2/3 = 7/4 : 2/5

       1/3 . x  : 2/3  = 35/8

        1/3 . x          = 35/8 . 2/3

         1/3 . x          = 35/12

                 x          = 35/12 : 1/3

                 x          = 35/4

   

23 tháng 7 2016

\(\frac{1}{3}x:\frac{2}{3}=1\frac{3}{4}:\frac{2}{5}\)

\(\Rightarrow\frac{1}{3}x:\frac{2}{3}=\frac{35}{8}\)

\(\Rightarrow\frac{1}{3}x=\frac{35}{12}\)

\(\Rightarrow x=\frac{35}{4}\)

a) \(\left(\frac{1}{3}\cdot x\right):\frac{2}{3}=1\frac{3}{4}:\frac{2}{5}\)

\(=\left(\frac{1}{3}\cdot x\right):\frac{2}{3}=\frac{35}{8}\)

\(\Rightarrow\frac{1}{3}\cdot x=\frac{35}{8}\cdot\frac{2}{3}\)

\(\Rightarrow x=\frac{35}{12}:\frac{1}{3}=\frac{35}{4}\)

b) \(4,5:0,3=2,5:\left(0,1\cdot x\right)\)

\(=15=2,5:\left(0,1\cdot x\right)\)

\(\Rightarrow0,1\cdot x=2,25:15\)

\(\Rightarrow x=\frac{3}{20}:0,1=\frac{3}{2}=1,5\)

c) \(8:\left(\frac{1}{4}\cdot x\right)=2:0,02\)

\(8:\left(\frac{1}{4}\cdot x\right)=100\)

\(\Rightarrow\frac{1}{4}\cdot x=8:100\)

\(\Rightarrow x=\frac{2}{25}:\frac{1}{4}=\frac{8}{25}=0,32\)

d) \(3:2\frac{1}{4}=\frac{3}{4}:\left(6\cdot x\right)\)

\(=\frac{4}{3}=\frac{3}{4}:\left(6:x\right)\)

\(\Rightarrow6\cdot x=\frac{3}{4}:\frac{4}{3}\)

\(\Rightarrow x=\frac{9}{16}:6=\frac{3}{32}=0,09375\)

14 tháng 7 2016

làm 1 bài mẫu nha

a) \(\left(\frac{1}{3}.x\right):\frac{2}{3}=\frac{25}{6}\)

\(\Rightarrow\frac{1}{3}x=\frac{25}{9}\)

\(\Rightarrow x=\frac{25}{9}:\frac{1}{3}\)

\(\Rightarrow x=\frac{25}{3}\)

các bài sau dễ lắm

a) \(\left(\frac{1}{3}x\right):\frac{2}{3}=1\frac{2}{3}:\frac{2}{5}\)

\(\Rightarrow\frac{1}{3}x:\frac{2}{3}=\frac{25}{6}\)

\(\Rightarrow\frac{1}{3}x=\frac{5}{3}\)

\(\Rightarrow x=\frac{5}{3}:\frac{1}{3}\)

\(\Rightarrow x=5\)

3 tháng 10 2017

a)\(\left(\frac{1}{3}.x\right):\frac{2}{3}=\frac{7}{4}.\frac{5}{2}\)

\(\left(\frac{1}{3}.x\right):\frac{2}{3}=\frac{35}{8}\)

\(\frac{1}{3}.x=\frac{35}{8}.\frac{2}{3}\)

\(\frac{1}{3}.x=\frac{35}{12}\)

\(x=\frac{35}{12}:\frac{1}{3}\)

\(x=\frac{35}{12}.\frac{3}{1}\)

\(x=\frac{35}{4}\)

b)\(\frac{4,5}{0,3}=\frac{2,25}{0,1.x}\)

\(4,5.\left(0,1.x\right)=2,25.0,3\)

\(4,5.\left(0,1.x\right)=0,675\)

\(0,1.x=0,675:4,5\)

\(0,1.x=0,15\)

\(x=0,15:0,1\)

\(x=1.5\)

c)\(\frac{8}{\frac{1}{4}.x}=\frac{2}{0,02}\)

\(\left(\frac{1}{4}.x\right).2=8.0,02\)

\(\left(\frac{1}{4}.x\right).2=0,16\)

\(\frac{1}{4}.x=0,16:2\)

\(\frac{1}{4}.x=0,08\)

\(x=0,08:\frac{1}{4}\)

\(x=0,32\)

d)\(\frac{3}{\frac{9}{4}}=\frac{\frac{3}{4}}{6.x}\)

\(3.\left(6.x\right)=\frac{3}{4}.\frac{9}{4}\)

\(3.\left(6.x\right)=\frac{27}{16}\)

\(6.x=\frac{27}{16}:3\)

\(6.x=\frac{9}{16}\)

\(x=\frac{9}{16}:6\)

\(x=\frac{3}{32}\)

HỌC TỐT ^^

16 tháng 7 2016

a)4,5:0,3=2,25:(0,1.x)

   2,25:(0,1.x)=15

   0,1.x=0,15

   x=0,15:0,1

   x=1,5

Vậy x=1,5

b)8:\(\left(\frac{1}{4}.x\right)\)=2:0,02

   8:\(\left(\frac{1}{4}.x\right)\)=100

       \(\left(\frac{1}{4}.x\right)\)=\(\frac{8}{100}\)

        x=\(\frac{8}{100}\):\(\frac{1}{4}\)

         x=\(\frac{8}{25}\)

Vậy x=\(\frac{8}{25}\)

c)\(3:2\frac{1}{4}=\frac{3}{4}:\left(6.x\right)\)

   \(\frac{3}{4}:\left(6.x\right)=\frac{4}{3}\)

    6.x=\(\frac{3}{4}:\frac{4}{3}\)

    6.x=\(\frac{9}{16}\)

    x=\(\frac{9}{16}\):6

    x=\(\frac{3}{32}\)

Vậy x=\(\frac{3}{32}\)

16 tháng 7 2016

a.

\(4,5\div0,3=2,25\div\left(0,1\times x\right)\)

\(2,25\div\left(0,1\times x\right)=15\)

\(0,1\times x=\frac{2,25}{15}\)

\(0,1\times x=0,15\)

\(x=\frac{0,15}{0,1}\)

\(x=1,5\)

b.

\(8\div\left(\frac{1}{4}\times x\right)=2\div0,02\)

\(8\div\left(\frac{1}{4}\times x\right)=100\)

\(\frac{1}{4}\times x=\frac{8}{100}\)

\(\frac{1}{4}\times x=\frac{2}{25}\)

\(x=\frac{2}{25}\div\frac{1}{4}\)

\(x=\frac{2}{25}\times4\)

\(x=\frac{8}{25}\)

c.

\(3\div2^1_4=\frac{3}{4}\div\left(6\times x\right)\)

\(\frac{3}{4}\div\left(6\times x\right)=3\div2,25\)

\(\frac{3}{4}\div\left(6\times x\right)=\frac{4}{3}\)

\(6\times x=\frac{3}{4}\div\frac{4}{3}\)

\(6\times x=\frac{3}{4}\times\frac{3}{4}\)

\(6\times x=\frac{9}{16}\)

\(x=\frac{9}{16}\div6\)

\(x=\frac{9}{16}\times\frac{1}{6}\)

\(x=\frac{3}{32}\)

Bài 1 : Thực hiện phép tính(1) D = \(1+\frac{1}{2}\left(1+2\right)+\frac{1}{3}\left(1+2+3\right)+...+\frac{1}{16}\left(1+2+...+16\right)\)(2) M =\(\frac{\frac{1}{99}+\frac{2}{98}+\frac{3}{97}+...+\frac{99}{1}}{\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+...+\frac{1}{100}}\)Bài 2 : Tìm x biết(1) \(x-\left\{x-\left[x-\left(-x+1\right)\right]\right\}=1\)(2) \(\left[\frac{1}{2}+\frac{1}{3}+...+\frac{1}{2016}\right]\cdot...
Đọc tiếp

Bài 1 : Thực hiện phép tính

(1) D = \(1+\frac{1}{2}\left(1+2\right)+\frac{1}{3}\left(1+2+3\right)+...+\frac{1}{16}\left(1+2+...+16\right)\)

(2) M =\(\frac{\frac{1}{99}+\frac{2}{98}+\frac{3}{97}+...+\frac{99}{1}}{\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+...+\frac{1}{100}}\)

Bài 2 : Tìm x biết

(1) \(x-\left\{x-\left[x-\left(-x+1\right)\right]\right\}=1\)

(2) \(\left[\frac{1}{2}+\frac{1}{3}+...+\frac{1}{2016}\right]\cdot x=\frac{2015}{1}+\frac{2014}{2}+...+\frac{1}{2015}\)

(3) \(\frac{x}{\left(a+5\right)\left(4-a\right)}=\frac{1}{a+5}+\frac{1}{4-a}\)

(4) \(\frac{x+2}{11}+\frac{x+2}{12}+\frac{x+2}{13}=\frac{x+2}{14}+\frac{x+2}{15}\)

(5) \(\frac{x+1}{2015}+\frac{x+2}{2014}+\frac{x+3}{2013}+\frac{x+4}{2012}+4=0\)

Bài 3 : 

(1) Cho : A =\(\frac{9}{1}+\frac{8}{2}+\frac{7}{3}+...+\frac{1}{9}\); B =\(\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+...+\frac{1}{10}\)

CMR : \(\frac{A}{B}\)Là 1 số nguyên

(2) Cho : D =\(\frac{1}{1001}+\frac{1}{1002}+\frac{1}{1003}+...+\frac{1}{2000}\)CMR : \(D< \frac{3}{4}\)

Bài 4 : Ký hiệu [x] là số nguyên lớn nhất không vượt quá x , gọi là phần nguyên của x.

VD : [1.5] =1 ; [3] =3 ; [-3.5] = -4

(1) Tính :\(\left[\frac{100}{3}\right]+\left[\frac{100}{3^2}\right]+\left[\frac{100}{3^3}\right]+\left[\frac{100}{3^4}\right]\)

(2) So sánh : A =\(\left[X\right]+\left[X+\frac{1}{5}\right]+\left[X+\frac{2}{5}\right]+\left[X+\frac{3}{5}\right]+\left[X+\frac{4}{5}\right]\)và B = [5x]. Biết x=3.7

0
8 tháng 3 2019

3. Tìm x biết: |15-|4.x||=2019

\(\Rightarrow\orbr{\begin{cases}15-\left|4x\right|=2019\\15-\left|4x\right|=-2019\end{cases}\Rightarrow\orbr{\begin{cases}\left|4x\right|=-2004\\\left|4x\right|=2034\end{cases}}}\)

vì \(4x\ge0\)\(\Rightarrow\)|4x|=2043\(\Rightarrow4x=2034\Rightarrow x=508,5\)

KL: x=508,5