\(\frac{-8}{x}=\frac{-x}{18}\)

b) \(\frac{...">

K
Khách

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

6 tháng 9 2020

a) \(\frac{-8}{x}=\frac{-x}{18}\)

=> x.(-x) = (-8).18

=> -x= -144

=> x2 = 144 => x = \(\pm12\)

b) \(\frac{2x+3}{6}=\frac{x-2}{5}\)

=> 5(2x + 3) = 6(x - 2)

=> 10x + 15 - 6x + 12 = 0

=> 4x + 27 = 0

=> 4x = -27

=> x = -27/4

c) \(\frac{x+1}{22}=\frac{6}{x}\)

=> x(x + 1) = 22.6 = 132

=> x(x + 1) = 11.12

=> x = 11

6 tháng 9 2020

\(\frac{-8}{x}=\frac{-x}{18}\)

\(\Leftrightarrow-8\cdot18=x\cdot\left(-x\right)\)

\(\Leftrightarrow-144=-x^2\)

\(\Leftrightarrow144=x^2\)

\(\Leftrightarrow\left(\pm12\right)^2=x^2\)

\(\Leftrightarrow\pm12=x\)

\(\frac{2x+3}{6}=\frac{x-2}{5}\)

\(\Leftrightarrow\left(2x+3\right)\cdot5=6\left(x-2\right)\)

\(\Leftrightarrow10x+15=6x-12\)

\(\Leftrightarrow10x-6x=-12-15\)

\(\Leftrightarrow4x=-27\)

\(\Leftrightarrow x=-\frac{27}{4}\)

\(\frac{x+1}{22}=\frac{6}{x}\)

\(\Leftrightarrow\left(x+1\right)x=22\cdot6\)

\(\Leftrightarrow\left(x+1\right)x=132\)

\(\Leftrightarrow\left(x+1\right)x=12\cdot11\)

\(\Leftrightarrow x=11\)

22 tháng 3 2019

\(\frac{x-1}{6}=\frac{1}{6}\Leftrightarrow6\left(x-1\right)=6\Leftrightarrow6x-6=6\Leftrightarrow6x=12\Leftrightarrow x=2\)

\(\frac{x-2}{5}=\frac{8}{10}=\frac{4}{5}\Leftrightarrow5\left(x-2\right)=4.5=20\Leftrightarrow5x-10=20\Leftrightarrow5x=30\Leftrightarrow x=6\)

\(\frac{x-1}{8}=\frac{1}{2}\Leftrightarrow2\left(x-1\right)=8\Leftrightarrow2x-2=8\Leftrightarrow2x=10\Leftrightarrow x=5\)

\(\text{ câu 1 mk nghĩ là so sánh chứ nhỉ?}\)

4 tháng 7 2016

a/ \(\frac{6}{7}x=\frac{18}{23}\)

\(x=\frac{18}{23}:\frac{6}{7}=\frac{21}{23}\)

b/ \(2\frac{1}{2}x=\frac{5}{6}\)

\(=>\frac{5}{2}x=\frac{5}{6}\)

\(x=\frac{5}{6}:\frac{5}{2}=\frac{1}{3}\)

c/\(x:2\frac{3}{4}=9\frac{5}{8}\)

\(x:\frac{11}{4}=\frac{77}{8}\)

\(x=\frac{77}{8}\cdot\frac{11}{4}=\frac{847}{32}\)

d/\(7\frac{1}{7}\cdot\frac{1}{7}\cdot x=22\frac{1}{8}\)

\(\frac{50}{49}x=\frac{177}{8}\)

\(x=\frac{177}{8}:\frac{50}{49}=\frac{8673}{400}\)

4 tháng 7 2016

\(a,\frac{6}{7}.x=\frac{18}{23}\) \(\Rightarrow x=\frac{18}{23}:\frac{6}{7}=\frac{18}{23}.\frac{7}{6}=\frac{21}{23}\)

\(b,2\frac{1}{2}.x=\frac{5}{6}\Rightarrow\frac{5}{2}.x=\frac{5}{6}\Rightarrow x=\frac{5}{6}:\frac{5}{2}=\frac{5}{6}.\frac{2}{5}=\frac{1}{3}\)

\(c,x:2\frac{3}{4}=9\frac{5}{8}\Rightarrow x:\frac{11}{4}=\frac{77}{8}\Rightarrow x=\frac{77}{8}.\frac{11}{4}=\frac{847}{32}\)

\(d,7\frac{1}{7}.\frac{1}{7}.x=22\frac{1}{8}\Rightarrow\frac{50}{49}.x=\frac{177}{8}\Rightarrow x=\frac{177}{8}:\frac{50}{49}=\frac{177}{8}.\frac{49}{50}=\frac{8673}{400}\)

8 tháng 5 2020

câu c: ( ảnh kia câu c mình chụp chưa rõ nên chụp lại nhe) chữ nó xấu gì đâu:)

Phép chia phân số

8 tháng 5 2020

Phép chia phân sốPhép chia phân số

11 tháng 8 2016

a) 2 - ( \(5\frac{3}{8}\)x  X  - \(\frac{5}{24}\)) = \(\frac{5}{12}\)

             \(5\frac{3}{8}\)x  X  - \(\frac{5}{24}\)= \(\frac{19}{12}\)

             \(5\frac{3}{8}\)x  X             = \(\frac{43}{24}\)

                            X             = \(\frac{1}{3}\)

b)  \(1\frac{2}{9}\): ( \(3\frac{1}{3}\)x  X + \(\frac{1}{6}\))  = \(\frac{22}{23}\)

                    \(3\frac{1}{3}\)x  X + \(\frac{1}{6}\)   = \(\frac{23}{18}\)

                   \(3\frac{1}{3}\)x  X                = \(\frac{10}{9}\)

                                  X                 =\(\frac{1}{3}\)

C)  \(\frac{4}{5}\)x    X  - \(\frac{1}{2}\)x    X + \(\frac{3}{4}\)x    X = \(\frac{7}{40}\)

  (   \(\frac{4}{5}-\frac{1}{2}+\frac{3}{4}\))  x   X                 = \(\frac{7}{40}\)

               \(\frac{21}{20}\)         x   X                      = \(\frac{7}{40}\)

                                       X                       =\(\frac{1}{6}\)

20 tháng 2 2017

a) \(-\frac{2x}{5}=\frac{-6}{3}\)

\(\Rightarrow-2x.3=-6.5\)

\(\Rightarrow-2x=\frac{-6.5}{3}\)

\(\Rightarrow-2x=-10\)

\(\Rightarrow x=\frac{-10}{-2}\)

\(\Rightarrow x=5\)

b) \(\frac{x-2}{18}=\frac{-1}{6}\)

\(\Rightarrow\left(x-2\right).6=-1.18\)

\(\Rightarrow x-2=\frac{-1.18}{6}\)

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

\(\Rightarrow x=-3+2\)

\(\Rightarrow x=-1\)

c) \(\frac{x}{14}=\frac{6}{y}=\frac{-15}{35}\)

\(\Rightarrow\left[\begin{matrix}\frac{x}{14}=\frac{-15}{35}\\\frac{6}{y}=\frac{-15}{35}\end{matrix}\right.\Rightarrow\left[\begin{matrix}x.35=-15.14\\6.35=-15.y\end{matrix}\right.\)

\(\Rightarrow\left[\begin{matrix}x=\frac{-15.14}{35}\\y=\frac{6.35}{-15}\end{matrix}\right.\Rightarrow\left[\begin{matrix}x=-6\\y=-14\end{matrix}\right.\)

Vậy \(x=-6;y=-14\)

20 tháng 2 2017

a) \(\frac{-2x}{5}=-\frac{6}{3}\)

\(\Leftrightarrow-6x=-30\)

\(\Leftrightarrow x=5\)

b) \(\frac{x-2}{18}=-\frac{1}{6}\)

\(\Leftrightarrow-6\left(x-2\right)=-18\)

\(\Leftrightarrow x-2=3\)

\(\Leftrightarrow x=5\)

c) \(\frac{x}{14}=\frac{6}{y}=-\frac{15}{35}\)

\(\Leftrightarrow\frac{x}{14}=\frac{6}{y}=-\frac{3}{7}\)

\(\Leftrightarrow\left\{\begin{matrix}x=-6\\y=-14\end{matrix}\right.\)

1 tháng 8 2020

a) \(\frac{x}{5}=\frac{2}{5}\Rightarrow x=\frac{2\cdot5}{5}=2\)

b)\(\frac{3}{8}=\frac{6}{x}\Rightarrow x=\frac{6\cdot8}{3}=16\)

c)\(\frac{1}{9}=\frac{x}{27}\Rightarrow x=\frac{27}{9}=3\)

d) \(\frac{4}{x}=\frac{8}{6}\Rightarrow x=\frac{4\cdot6}{8}=3\)

e)

\(\frac{3}{x-5}=-\frac{4}{x+2}\\ \Rightarrow3\left(x+2\right)=-4\left(x-5\right)\\ \Leftrightarrow3x+6=-4x+20\\ \Leftrightarrow3x+6+4x-20=0\\ \Leftrightarrow7x-14=0\\ \Leftrightarrow x=2\)

\(g,\frac{x}{-2}=-\frac{8}{x}\Rightarrow x^2=16\Leftrightarrow\left[{}\begin{matrix}x=4\\x=-4\end{matrix}\right.\)

Vậy có 2 giá trị của x là 4 ; -4

a) Ta có: \(\frac{x}{5}=\frac{2}{5}\)

\(\Leftrightarrow x=\frac{2\cdot5}{5}=2\)

Vậy: x=2

b) Ta có: \(\frac{3}{8}=\frac{6}{x}\)

\(\Leftrightarrow x=\frac{6\cdot8}{3}=\frac{48}{3}=16\)

Vậy: x=16

c) Ta có: \(\frac{1}{9}=\frac{x}{27}\)

\(\Leftrightarrow x=\frac{1\cdot27}{9}=\frac{27}{9}=3\)

Vậy: x=3

d) Ta có: \(\frac{4}{x}=\frac{8}{6}\)

\(\Leftrightarrow x=\frac{4\cdot6}{8}=\frac{24}{8}=3\)

Vậy: x=3

e) Ta có: \(\frac{3}{x-5}=\frac{-4}{x+2}\)

\(\Leftrightarrow3\cdot\left(x+2\right)=-4\cdot\left(x-5\right)\)

\(\Leftrightarrow3x+6=-4x+20\)

\(\Leftrightarrow3x+6+4x-20=0\)

\(\Leftrightarrow7x-14=0\)

\(\Leftrightarrow7x=14\)

hay x=2

Vậy: x=2

g) Sửa đề: \(\frac{x}{-2}=\frac{-8}{x}\)

Ta có: \(\frac{x}{-2}=\frac{-8}{x}\)

\(\Leftrightarrow x^2=\left(-8\right)\cdot\left(-2\right)=16\)

hay x∈{4;-4}

Vậy: x∈{4;-4}

a, \(\frac{3}{7}=-\frac{x}{21}\Leftrightarrow63=-7x\Leftrightarrow x=-9\)

b, \(\frac{x-1}{6}=\frac{2}{3}\Leftrightarrow\frac{x-1}{6}=\frac{4}{6}\Leftrightarrow x-1=4\Leftrightarrow x=5\)

c, \(\frac{-15}{2x+3}=\frac{-5}{8}\Leftrightarrow-120=-10x-15\Leftrightarrow-10x=-105\Leftrightarrow x=10,5\)( chưa xem lại ko chắc , thử lại giúp mk nha ) 

7 tháng 5 2020

a) \(\frac{3}{7}=\frac{-x}{21}\)

\(\Rightarrow-7x=21.3\)

        \(-7x=63\)

               \(x=63:\left(-7\right)\)

               \(x=-9\)

Vậy x=-9

b) \(\frac{x-1}{6}=\frac{2}{3}\)

\(\Rightarrow\left(x-1\right).3=6.2\)

             \(3x-3=12\)

                       \(3x=12+3\)

                       \(3x=15\)

                          \(x=15:3\) 

                          \(x=5\)

Vậy x=5

1 tháng 7 2019

a) \(2x-\frac{2}{3}-7x=\frac{3}{2}-1\\ 2x-7x-\frac{2}{3}=\frac{1}{2}\\ -5x=\frac{1}{2}+\frac{2}{3}\\ -5x=\frac{7}{6}\\ x=\frac{7}{6}:\left(-5\right)\\ x=\frac{-7}{30}\)Vậy \(x=\frac{-7}{30}\)

b) \(\frac{3}{2}x-\frac{2}{5}=\frac{1}{3}x-\frac{1}{4}\\ \frac{3}{2}x-\frac{1}{3}x=\frac{2}{5}-\frac{1}{4}\\ \frac{7}{6}x=\frac{3}{20}\\ x=\frac{3}{20}:\frac{7}{6}\\ x=\frac{9}{70}\)Vậy \(x=\frac{9}{70}\)

c) \(\frac{2}{3}-\frac{5}{3}x=\frac{7}{10}x+\frac{5}{6}\\ \frac{2}{3}-\frac{5}{6}=\frac{7}{10}x+\frac{5}{3}x\\ \frac{-1}{6}=\frac{71}{30}x\\ x=\frac{-1}{6}:\frac{71}{30}\\ x=\frac{-5}{71}\)Vậy \(x=\frac{-5}{71}\)

d) \(2x-\frac{1}{4}=\frac{5}{6}-\frac{1}{2}x\\ 2x+\frac{1}{2}x=\frac{5}{6}+\frac{1}{4}\\ \frac{5}{2}x=\frac{13}{12}\\ x=\frac{13}{12}:\frac{5}{2}\\ x=\frac{13}{30}\)Vậy \(x=\frac{13}{30}\)

e) \(3x-\frac{5}{3}=x-\frac{1}{4}\\ 3x-x=\frac{5}{3}-\frac{1}{4}\\ 2x=\frac{17}{12}\\ x=\frac{17}{12}:2\\ x=\frac{17}{24}\)Vậy \(x=\frac{17}{24}\)

1 tháng 7 2019

Èo, chăm thế? Chăm hơn cả mik cơ, gần 11 h rồi onl thì thấy bài được bạn HISI làm hết rồi :((