a, \(\dfrac{4x}{7}=\dfrac{1}{5}+\dfrac{2}{3}=\dfrac{3+10}{15}=\dfrac{13}{15}\Rightarrow60x=91\Leftrightarrow x=\dfrac{91}{60}\)

b, \(\dfrac{5}{7}:x=\dfrac{1}{6}+\dfrac{4}{5}=\dfrac{5+24}{30}=\dfrac{29}{30}\Leftrightarrow x=\dfrac{5}{7}:\dfrac{29}{30}=\dfrac{150}{203}\)

5/6 : x= 1/6 - 4/5 

5/6 : x= -19/30

x = 5/6 : (-19)/30

x = -25/19

\(x=\dfrac{5}{6}:\left(\dfrac{1}{6}-\dfrac{4}{5}\right)=\dfrac{5}{6}:\left(-\dfrac{19}{30}\right)=-\dfrac{25}{19}\)

\(\dfrac{5}{6}:x=\dfrac{1}{6}-\dfrac{4}{5}\)
\(\dfrac{5}{6}:x=-\dfrac{19}{30}\)
      \(x=\dfrac{5}{6}:\left(-\dfrac{19}{30}\right)\)
      \(x=-\dfrac{25}{19}\)

a) 11 - 3(2x - 1) = -8x + 5

⇔ 11 - 6x + 3 = -8x + 5

⇔ -6x + 8x = 5 - 11 - 3

⇔ 2x = -9

⇔ x = -9/2

Vậy S = {-9/2}

b) (x - 3)/5 + (1 + 2x)/3 = 6

⇔ 3(x - 3) + 5(1 + 2x) = 6.15

⇔ 3x - 9 + 5 + 10x = 90

⇔ 13x = 90 + 9 - 5

⇔ 13x = 94

⇔ x = 94/13

Vậy S = {94/13}

\(a,\dfrac{3}{4}:\dfrac{6}{x}=\dfrac{5}{4}\\ \dfrac{6}{x}=\dfrac{3}{4}:\dfrac{5}{4}\\ \dfrac{6}{x}=\dfrac{3}{5}\\ x=6:\dfrac{3}{5}\\ x=10\\ b,\left(x+\dfrac{7}{4}\right)\times\dfrac{2}{3}=6\\ x+\dfrac{7}{4}=6:\dfrac{2}{3}\\x+\dfrac{7}{4}=9\\ x=9-\dfrac{7}{4}\\ x=\dfrac{29}{4}\)

giúp mình đi, sao dạo này ít ngừi giúp qué zại

a) \(\dfrac{3}{4}\div\dfrac{6}{x}=\dfrac{5}{4}\)

            \(\dfrac{6}{x}=\dfrac{3}{4}\div\dfrac{5}{4}\)

            \(\dfrac{6}{x}=\dfrac{3}{5}\)

            \(x=\left(6\div3\right)\times5\)

           \(x=10\)

b) \(\left(x+\dfrac{7}{4}\right)\times\dfrac{2}{3}=6\)

     \(x+\dfrac{7}{4}=6\div\dfrac{2}{3}\)

     \(x+\dfrac{7}{4}=9\)

     \(x=9-\dfrac{7}{4}\)

    \(x=\dfrac{29}{4}\)

`7/9 xx 3/14 : 5/6`

`= 1/6 : 5/6`

`= 1/6  xx 6/5`

`= 1/5`.

=1/6:5/6

=1/5

0.2

giúp mình với đi mà

\(a.y:\dfrac{2}{3}=\dfrac{4}{9}\times3\\y:\dfrac{2}{3}=\dfrac{4}{3}\\ y=\dfrac{4}{3}\times\dfrac{2}{3}\\ y=\dfrac{8}{9}\\ b.\dfrac{5}{6}+\dfrac{y}{12}=\dfrac{7}{6}\\ \dfrac{y}{12}=\dfrac{7}{6}-\dfrac{5}{6}\\ \dfrac{y}{12}=\dfrac{2}{6}\\ y\times6=12\times2=24\\ y=24:6\\ y=4 \)

\(a,y:\dfrac{2}{3}=\dfrac{4}{9}.3\)

\(y:\dfrac{2}{3}=\dfrac{4}{3}\)

\(y=\dfrac{4}{3}.\dfrac{2}{3}\)

\(y=\dfrac{8}{9}\)

\(b,\dfrac{5}{6}+\dfrac{y}{12}=\dfrac{7}{6}\)

\(\dfrac{y}{12}=\dfrac{7}{6}-\dfrac{5}{6}\)

\(\dfrac{y}{12}=\dfrac{2}{6}\)

\(y.6=12.2\)

\(y.6=24\)

\(y=24:6\)

\(y=4\)

\(\left(y-\dfrac{2}{3}\right):\dfrac{4}{5}=\dfrac{5}{6}\)

\(y-\dfrac{2}{3}=\dfrac{5}{6}\times\dfrac{4}{5}\)

\(y-\dfrac{2}{3}=\dfrac{2}{3}\)

\(y=\dfrac{2}{3}+\dfrac{2}{3}\)

\(y=\dfrac{4}{3}\)

\(y-\dfrac{2}{3}=\dfrac{5}{6}\times\dfrac{4}{5}\)

\(y-\dfrac{2}{3}=\dfrac{2}{3}\)

\(y=\dfrac{2}{3}+\dfrac{2}{3}\)

\(y=\dfrac{4}{3}\)

y – 2/3 = 5/6 x 4/5

y – 2/3 = 2/3

y= 2/3 + 2/3

y = 4/3

\(x\times\dfrac{3}{5}=\dfrac{2}{3}+\dfrac{1}{6}=\dfrac{5}{6}\)

\(x=\dfrac{5}{6}:\dfrac{3}{5}=\dfrac{25}{18}\)

X x 3/5 = 5/6
X          = 5/6 : 3/5
X          = 25/18

\(x\times\dfrac{3}{5}=\dfrac{2}{3}+\dfrac{1}{6}\)

\(x\times\dfrac{3}{5}=\dfrac{4}{6}+\dfrac{1}{6}\)

\(x\times\dfrac{3}{5}=\dfrac{5}{6}\)

\(x=\dfrac{5}{6}:\dfrac{3}{5}\)

\(x=\dfrac{5}{6}\times\dfrac{5}{3}\)

\(x=\dfrac{25}{18}\)

\(\dfrac{5\cdot4^{15}\cdot9^9-4\cdot3^{20}\cdot8^9}{5\cdot2^{29}\cdot9^{10}-7\cdot2^{29}\cdot27^6}\)

\(=\dfrac{5\cdot2^{30}\cdot3^{18}-2^2\cdot2^{27}\cdot3^{20}}{5\cdot2^{29}\cdot3^{20}-7\cdot2^{29}\cdot3^{18}}\)

\(=\dfrac{2^{29}\cdot3^{18}\left(5\cdot2-3^2\right)}{2^{29}\cdot3^{18}\left(5\cdot3^2-7\right)}\)

\(=\dfrac{10-9}{5\cdot9-7}=\dfrac{1}{38}\)