0,75 : 4,5 = \(\dfrac{1}{15}\) : (2x)

\(\Rightarrow\) \(\dfrac{1}{6}\) = \(\dfrac{1}{30}\) : x

\(\Rightarrow\) \(\dfrac{1}{30}\) : \(\dfrac{1}{6}\) = x

\(\Rightarrow\) x = \(\dfrac{1}{5}\)

0,75 : 4,5 = 1/15 : (2x)

1/6 = 1/15 : (2x)

(2x) = 1/15 : 1/6

2x = 2/5

x = 2/5 : 2

x = 1/5

Vậy x = 1/5

chúc bn hc tốt môn toán

đó là đáp án đúng đó ạk

a/ -4x(x - 5) - 2x(8 - 2x) = -3

  => -4x² + 20x - 16x + 4x² = -3

  => 4x = -3

   => x = -3/4

b/ \(\frac{x-1}{-15}=-\frac{60}{x-1}\Rightarrow\left(x-1\right)^2=\left(-60\right)\left(-15\right)\)

      \(\Rightarrow\left(x-1\right)^2=900\Rightarrow\orbr{\begin{cases}x-1=30\\x-1=-30\end{cases}\Rightarrow\orbr{\begin{cases}x=31\\x=-29\end{cases}}}\)

                                                        Vậy x = -29 , x = 31

a) 0,75 : 4,5 = \(\frac{1}{15}\) : 2x

=> \(\frac{0,75}{4,5}\) = \(\frac{\frac{1}{15}}{2x}\)

=> 0,75 . 2x = \(\frac{1}{15}\) . 4,5

=> 0,75 . 2x = 0,3

=> 2x            = 0,3 : 0,75

=> 2x            = 0,4

=> x               = 0,4 : 2

=>x                = 0,2

Ta có: 0,75:4,5= \(\frac{1}{15}\):(2x)

suy ra \(\frac{1}{6}\)=\(\frac{1}{15}\):(2x)

suy ra 2x = \(\frac{1}{15}:\frac{1}{6}\)

suy ra 2x= \(\frac{2}{5}\)

suy ra x= \(\frac{1}{5}\)

Vậy x=...

a/ 2x - 10 - [3x - 14 - (4 - 5x) - 2x] = 2

=> 2x - 10 - (3x - 14 - 4 + 5x - 2x) = 2

=> 2x - 10 - 3x + 14 + 4 - 5x + 2x = 2

=> -4x + 6 = 0

=> -4x = -6

=> x = 3/2

b/ \(\left(\frac{1}{4}x-1\right)+\left(\frac{5}{6}x-2\right)-\left(\frac{3}{8}x+1\right)=4,5\)

\(\Rightarrow\frac{1}{4}x-1+\frac{5}{6}x-2-\frac{3}{8}x-1-\frac{9}{2}=0\)

\(\Rightarrow\frac{17}{24}x-\frac{17}{2}=0\)

\(\Rightarrow\frac{17}{24}x=\frac{17}{2}\)

\(\Rightarrow x=12\)

\(=\frac{16}{5}.\frac{15}{16}-\left(\frac{3}{4}+\frac{2}{7}\right):\left(\frac{-29}{28}\right)\)

\(=3-\left(\frac{21}{28}+\frac{8}{28}\right):\left(\frac{-29}{28}\right)\)

\(=3-\left(\frac{29}{28}\right).\left(\frac{-28}{29}\right)\)

\(=3-\left(-1\right)\)

\(=4\)

b)   \(=\left(\frac{1}{4}+\frac{25}{2}-\frac{5}{16}\right):\left(12-\frac{7}{12}:\left(\frac{3}{8}-\frac{1}{12}\right)\right)\)

       \(=\left(\frac{4}{16}+\frac{200}{16}-\frac{5}{16}\right):\left(12-\frac{7}{12}:\left(\frac{3.3}{2.3.4}-\frac{2}{2.3.4}\right)\right)\)

     \(=\left(\frac{199}{16}\right):\left(12-\frac{7}{12}:\left(\frac{9}{24}-\frac{2}{24}\right)\right)\)

      \(=\frac{199}{16}:\left(12-\frac{7}{12}.\frac{24}{7}\right)\)

    \(=\frac{199}{16}:\left(12-2\right)\)

\(=\frac{199}{16}:10\)

\(=\frac{199}{160}\)

c)   \(\left(\frac{-3}{5}+\frac{5}{11}\right):\frac{-3}{7}+\left(\frac{-2}{5}+\frac{6}{5}\right):\frac{-3}{7}\)

\(\left(\frac{-33}{55}+\frac{25}{55}\right):\frac{-3}{7}+\left(\frac{4}{5}\right):\frac{-3}{7}\)

\(\left(\frac{-8}{55}\right).\frac{-7}{3}+\frac{4}{5}.\frac{-7}{3}\)

\(\frac{-7}{3}\left(\frac{-8}{55}+\frac{4}{5}\right)\)

\(\frac{-7}{3}.\frac{36}{55}=\frac{-84}{55}\)

giờ mk phải đi ngủ r mai mk làm cho 

nhớ làm giúp mình nhá mai mình phải đi học r :<

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

\(\Leftrightarrow\left(4,5-2x\right):\frac{3}{4}=\frac{4}{3}\)

\(\Leftrightarrow4,5-2x=1\)

\(\Leftrightarrow2x=3,5\)

\(\Leftrightarrow x=1,75\)

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

\(4,5-2x=1\frac{1}{3}\cdot\frac{3}{4}\)

\(4,5-2x=1\)

\(2x=4,5-1=3,5\)

\(x=3,5:2=1,75\)

Vậy .........................

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

\(\left(4,5-2x\right)=\)\(1\frac{1}{3}x\frac{3}{4}\)

\(\left(4,5-2x\right)=1\)

\(2x=1+4,5\)

\(2x=5,5\)

\(x=5,5:2\)

\(x=2,75\)

Vậy x = 2,75

Học tốt~~~

a) \(\left|x+3\right|:\left(-15\right)=\frac{1}{3}\)

\(\left|x+3\right|=-5\)

=> không tìm được x

b) \(\left|4,5-2x\right|.\left(-1\frac{4}{7}\right)=-\frac{11}{14}\)

\(\left|4,5-2x\right|=2\)

TH1: 4,5 - 2x = 2

2x = 2,5

x = 1,25

TH2: 4,5 - 2x = -2

2x = 6,5

x = 3,25

KL:...