a, 3/4 + 1/4.x=2

    1/4.x        = 2-3/4

     1/4.x      =5/4

     x           = 5/4:1/4

     x           = 5

b, x-2/3.9/4=2,5-1/2

    x-2/3.9/4=2

    x-2/3     =2:9/4

    x-2/3   =8/9

     x        = 8/9+2/3

     x         = 14/9

c, 2.x+1/3=4/3

    2.x      =4/3-1/3

    2.x      =1

       x      =11:2

       x      = 1/2

\(lim\left(50.\dfrac{1-\left(\dfrac{4}{5}\right)^n}{1-\dfrac{4}{5}}+\dfrac{4}{5}.50.\dfrac{1-\left(\dfrac{4}{5}\right)^{n-1}}{1-\dfrac{4}{5}}\right)\) \(=50.\dfrac{1}{\dfrac{1}{5}}+\dfrac{4}{5}.50.\dfrac{1}{\dfrac{1}{5}}=450\)

\(x\cdot\frac{1}{2}\cdot\frac{1}{3}=\frac{3}{4}\\ x\cdot\frac{1}{6}=\frac{3}{4}\\ x=\frac{3}{4}:\frac{1}{6}\\ x=\frac{9}{2}\)

Vậy.....

\(x\times\frac{1}{2}\times\frac{1}{3}=\frac{3}{4}\)

\(x=\frac{3}{4}\div\frac{1}{3}\div\frac{1}{2}\)

\(x=\frac{9}{2}\)

\(X\text{ × }\frac{1}{2}\text{ × }\frac{1}{3}=\frac{3}{4}\)

\(X\text{ × }\frac{1}{6}=\frac{3}{4}\)

\(X=\frac{3}{4}:\frac{1}{6}\)

\(X=\frac{9}{2}\)

hình như là 6666666.6

Ta có:

\(\frac{1}{3.4}.x+\frac{1}{4.5}.x+...+\frac{1}{49.50}.x=1\)

\(\Rightarrow x.\left(\frac{1}{3.4}+\frac{1}{4.5}+...+\frac{1}{49.50}\right)=1\)

\(\Rightarrow x.\left(\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+...+\frac{1}{49}-\frac{1}{50}\right)=1\)

\(\Rightarrow x.\left(\frac{1}{3}-\frac{1}{50}\right)=1\Leftrightarrow x.\frac{47}{150}=1\)

\(\Rightarrow x=1:\frac{47}{150}\Leftrightarrow x=\frac{150}{47}\)

\(\frac{1}{2}.x-\frac{3}{4}=\frac{5}{6}\)

\(\frac{1}{2}.x=\frac{5}{6}+\frac{3}{4}\)

\(\frac{1}{2}.x=\frac{19}{12}\)

\(x=\frac{19}{12}:\frac{1}{2}\)

\(x=\frac{19}{6}\)

Vậy \(x=\frac{19}{6}\)

\(\frac{1}{2}\)x X = \(\frac{5}{6}\)+ \(\frac{3}{4}\)

\(\frac{1}{2}\)x X = \(\frac{19}{12}\)

X = \(\frac{19}{12}\): \(\frac{1}{2}\)

X = \(\frac{19}{6}\)

1/2 x X - 3/4 = 5/6

1/2 x X = 5/6 + 3/4

1/2 x X = 19/12

X = 19/12 : 1/2

X = 19/6

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

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

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

\(x=\frac{2}{5}:\frac{3}{4}\)

\(x=\frac{8}{15}\)

2 chữ x hả bạn

(3X x):1/2=4/5

=>3 X x=4/5x1/2

=> 3 X x= 2/5

=> x=2/5:3

=>x=2/15

Mình nghĩ bạn nên chia thành 5 phần để trả lời nhanh hơn !

có nghĩa là sao

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

=>\(\frac{3}{4}x=\frac{4}{5}.\frac{1}{2}\)

=>\(\frac{3}{4}x=\frac{2}{5}\)

=>\(x=\frac{2}{5}:\frac{3}{4}\)

=>\(x=\frac{8}{15}\)

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

\(\left(\frac{3}{4}.x\right)=\frac{2}{5}\)

\(\Rightarrow x=\frac{2}{5}:\frac{3}{4}=\frac{8}{15}\)

k nha

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

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

\(\left(\frac{3}{4}.x\right)=\frac{2}{5}\)

\(x=\frac{2}{5}:\frac{3}{4}\)

\(x=\frac{8}{15}\)