Chọn B nha

HT

a) \(4,9x+\frac{x}{10}=10,2\)

<=>49x+x=102

<=>50x=102

<=>x=102:50

<=>x=2,04

b)\(4,1x-\frac{x}{10}=2,4\)

<=>41x-x=24

<=>40x=24

<=>x=24:40

<=>x=0,6

nhanh nhất k nha bạn :))

a) X x 4,9 + X : 10 = 10,2

x (4,9 + 1/10) = 10,2

x* 5 = 10,2

x= 51/25

b) X x 4,1 - X : 10 = 2,4

x(4,1 - 1/10) =2,4

x* 4 = 2,4

x=3/5

X x4,9 + X x 0,1 =3,04

a, \(\dfrac{3}{7}\)\(x\) - 0,4 = - \(\dfrac{17}{35}\)

    \(\dfrac{3}{7}\)\(x\)         = - \(\dfrac{17}{35}\) + 0,4

     \(\dfrac{3}{7}\)\(x\)       = - \(\dfrac{3}{35}\)

        \(x\)       = - \(\dfrac{3}{35}\): \(\dfrac{3}{7}\)

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

b, 0,2.(\(x\) - 3) +2,4 = 10

    0,2.(\(x\) - 3)          = 10 - 2,4

    0,2.(\(x\) - 3)          = 7,6

           \(x\) - 3            = 7,6:0,2

           \(x\) - 3            = 38

            \(x\)                = 38 + 3

             \(x\)                = 41

\(\dfrac{3}{7}x-0,4=\dfrac{-17}{35}\)

\(\dfrac{3}{7}x=\dfrac{-17}{35}+0,4=\dfrac{-34}{70}+\dfrac{28}{70}\)

\(\dfrac{3}{7}x=\dfrac{-6}{70}=\dfrac{-3}{35}\)

\(x=\dfrac{-3}{35}:\dfrac{3}{7}=\dfrac{-3}{35}\cdot\dfrac{7}{3}\)

\(x=\dfrac{3\cdot\left(-1\right)\cdot7}{5\cdot7\cdot3}=-\dfrac{1}{5}\)

b) \(0,2\left(x-3\right)+2,4=10\)

\(0,2\left(x-3\right)=10-2,4=7,6\)

\(x-3=7,6:0,2=38\)

\(x=38+3=41\)

c) \(\left(x:2,2\right)\cdot\dfrac{1}{6}=\dfrac{-3}{8}\cdot\left(0,5-1\dfrac{3}{5}\right)\)

\(\left(x:2,2\right)\cdot\dfrac{1}{6}=\dfrac{-3}{8}\cdot\dfrac{-11}{10}\)

\(x:2,2=\dfrac{-3}{8}\cdot\dfrac{-11}{10}\cdot\dfrac{6}{1}\)

\(x:2,2=\dfrac{-3\cdot\left(-11\right)\cdot2\cdot3}{2\cdot4\cdot10\cdot1}=\dfrac{99}{40}\)

\(x=\dfrac{99}{40}\cdot2,2=\dfrac{99}{40}\cdot\dfrac{22}{10}\)

\(x=\dfrac{99\cdot2\cdot11}{40\cdot2\cdot5}=\dfrac{1089}{200}\)

A.  x - 3,5  =  2,4 + 1,5

              x  =  3,9 + 3,5

              x  =  7,4

B.  x + 6,14  =  27,8 - 8,6

               x  =  19,2 - 6,14 

                  x  = 12,8

C.  4,3 x  x  =  3,8 x 4,3

                x  =  3,8 x 4,3 : 4,3

                x  =  3,8

D.   7, 3 x x + 2,7 x x = 10

       x x ( 7, 3  + 2,7 ) = 10

                               x  = 10 : 10

                               x = 1

x=30 nha bạn

Nhớ k cho mình nha

Chúc các bạn học giỏi

số đó là 25

nhớ

x=30

ai k mik mik k lại

X * 2,4 + X *1/10 =10

X * (2,4+1/10)= 10

X*5/2=10

X=10:5/2

X=4

x*2.4+x:10=10

=>x*(2.4+1/10)=10

=>x*5/2=10

=>x=10:5/2

x=10*2/5

x=4

nếu thấy đúng thì k cho mh nha

x.2,4+x:10=10

=> x.2,4+x.0,1=10

=> x.(2,4+0,1) =10

=> x.2,5          =10

=> x                =10:2,5

=> x                =4

Vậy x=4

a)

\(\begin{array}{l}x + \left( { - \frac{1}{5}} \right) = \frac{{ - 4}}{{15}}\\x = \frac{{ - 4}}{{15}} + \frac{1}{5}\\x = \frac{{ - 4}}{{15}} + \frac{3}{{15}}\\x = \frac{{ - 1}}{{15}}\end{array}\)                 

Vậy \(x = \frac{{ - 1}}{{15}}\).

b)

\(\begin{array}{l}3,7 - x = \frac{7}{{10}}\\x = 3,7 - \frac{7}{{10}}\\x = \frac{{37}}{{10}} - \frac{7}{{10}}\\x=\frac{30}{10}\\x = 3\end{array}\)

Vậy \(x = 3\).

c)

\(\begin{array}{l}x.\frac{3}{2} = 2,4\\x.\frac{3}{2} = \frac{{12}}{5}\\x = \frac{{12}}{5}:\frac{3}{2}\\x = \frac{{12}}{5}.\frac{2}{3}\\x = \frac{8}{5}\end{array}\)

Vậy \(x = \frac{8}{5}\)       

d)

\(\begin{array}{l}3,2:x =  - \frac{6}{{11}}\\\frac{{16}}{5}:x =  - \frac{6}{{11}}\\x = \frac{{16}}{5}:\left( { - \frac{6}{{11}}} \right)\\x = \frac{{16}}{5}.\frac{{ - 11}}{6}\\x = \frac{{ - 88}}{{15}}\end{array}\)

Vậy \(x = \frac{{ - 88}}{{15}}\).