a,3/4 . (-5/12)+3/4.(-7/12)

` 3/4 . [ - ( 5/12 + 7/12  ) ] `

`3/4 . (-1) = -3/4 `

`2/3 . x - 0,5 = 3/4 `

`        x - 0,5 = 3/4 - 2/3 `

`        x-0,5 = 1/12 `

`        x =       1/12 + 0,5 `

`        x= 7/12 `

a, 3/4 . (-5/12)+3/4.(-7/12) 

= 3/4 . [(-5/12) + (-7/12)]

= 3/4 . (-1)

= -3/4

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a, 2/3 .x-0,5=3/4

2/3 . x = 3/2 + 0,5

2/3 . x = 2 

x = 2 : 2/3

x = 3 

vậy x = 3

Bài 2:

a: =>2/3x=3/4+1/2=3/4+2/4=5/4

=>x=5/4:2/3=5/4*3/2=15/8

b:=>-2x+4=3x-12

=>-5x=-16

=>x=16/5

0,5.x-2/3.x=5/12

(0,5-2/3).x =5/12

(-1/6).x        =5/12

x               =5/12:(-1/6)

x                =-5/2

Vậy x=-5/2

Pt \(\Leftrightarrow\dfrac{1}{2}x-\dfrac{2}{3}x=\dfrac{5}{12}\)
\(\Leftrightarrow x\left(\dfrac{1}{2}-\dfrac{2}{3}\right)=\dfrac{5}{12}\)
\(\Leftrightarrow-\dfrac{1}{6}.x=\dfrac{5}{12}\)
\(\Leftrightarrow x=-\dfrac{5}{2}\)

0,5.x-\(\dfrac{2}{3}\).x=\(\dfrac{5}{12}\)

\(\Leftrightarrow\)\(\dfrac{1}{2}\).x-\(\dfrac{2}{3}\).x=\(\dfrac{5}{12}\)

\(\Leftrightarrow\)x.(\(\dfrac{1}{2}\)-\(\dfrac{2}{3}\))=\(\dfrac{5}{12}\)

\(\Leftrightarrow\)x.\(\dfrac{-1}{6}\) =\(\dfrac{5}{12}\)

\(\Leftrightarrow\)x =\(\dfrac{5}{12}\):\(\dfrac{-1}{6}\)

\(\Leftrightarrow\)x =\(\dfrac{5}{12}\).\(\dfrac{-6}{1}\)

\(\Leftrightarrow\)x = \(\dfrac{-5}{2}\)

5 x 12 x 3 x 7 / 3 x 8 x 7 x 5 = 3/2

2 x 5 x 4 x 6 / 4 x 3 x 5 x 7 = 4/7

5 x 12 x 3 x 7 / 3 x 8 x 7 x 5

=5 x 3 x 7 x 12/ 3 x 7 x 5 x 8

= 12/8 = 3/2

2 x 5 x 4 x 6 / 4 x 3 x 5 x 7 

=4/7

\(\frac{5.12.3.7}{3.8.7.5}=\frac{12}{8}=\frac{3}{2}\\ \)

2) \(\frac{2.5.4.6}{4.3.5.7}=\frac{12}{21}=\frac{4}{7}\)

x:4=7-3

x:4=4

x=4x4

x=16

Ai

x=16 đó

x:4=4

x=4x4

x=16

học tốt

Giup minh voi

\(2\frac{2}{3}:x=1\frac{8}{9}:0,02\)

\(\frac{8}{3}:x=\frac{17}{9}:\frac{1}{50}\)

\(\frac{8}{3}:x=\frac{17}{9}.50\)

\(\frac{8}{3}:x=\frac{850}{9}\)

      \(x=\frac{8}{3}:\frac{850}{9}\)

      \(x=\frac{8}{3}x\frac{9}{850}\)

      \(x=\frac{12}{425}\)

Vậy \(x=\frac{12}{425}\)

\(-\frac{3}{5}:\frac{3}{14}+0,5.x=12\)

\(a.x+\dfrac{1}{6}=-\dfrac{3}{8}\)

\(\Leftrightarrow x=-\dfrac{13}{24}\)

\(b.2-\left(\dfrac{3}{4}-x\right)=\dfrac{7}{12}\)

\(\Leftrightarrow2-\dfrac{3}{4}+x=\dfrac{7}{12}\)

\(\Leftrightarrow x=-\dfrac{2}{3}\)

\(c.\dfrac{1}{2}x+\dfrac{1}{8}x=\dfrac{3}{4}\)

\(\Leftrightarrow\dfrac{5}{8}x=\dfrac{3}{4}\)

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

\(d.75\%-1\dfrac{1}{2}+0,5:\dfrac{5}{12}-\left(\dfrac{-1}{2}\right)^2\)

\(=\dfrac{75}{100}-\dfrac{3}{2}+\dfrac{1}{2}:\dfrac{5}{12}-\dfrac{1}{4}\)

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

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

a) \(x+\dfrac{1}{6}=\dfrac{-3}{8}\)

            \(x=\dfrac{-3}{8}-\dfrac{1}{6}\)

           \(x=\dfrac{-13}{24}\)

vậy x =....

b) \(2-\left(\dfrac{3}{4}-x\right)=\dfrac{7}{12}\)

             \(\dfrac{3}{4}-x=2-\dfrac{7}{12}\)

             \(\dfrac{3}{4}-x=\dfrac{17}{12}\)

                    \(x=\dfrac{3}{4}-\dfrac{17}{12}\)

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

vậy x =....