a)\(\frac{5}{9}\times x-1=\frac{8}{9}\)

\(\frac{5}{9}\times x=\frac{8}{9}+1\)

\(\frac{5}{9}\times x=\frac{17}{9}\)

\(x=\frac{17}{9}:\frac{5}{9}\)

\(x=\frac{17}{5}\)

b)\(x+x\times\frac{1}{3}:\frac{2}{9}+x:\frac{2}{7}=252\)

\(x+x\times\frac{3}{2}+x:\frac{2}{7}=252\)

\(x.1+x.\frac{3}{2}+x.\frac{7}{2}=252\)

\(x\left(1+\frac{3}{2}+\frac{7}{2}\right)=252\)

\(x\times6=252\)

\(x=252:6\)

\(x=42\)

a,5/9.x-1=8/9

5/9.x=17/9

x=17/5

b,x+x.1/3:2/9+x:2/7=252

x+x.1/3.9/2+x.7/2=252

x(1+1/3.9/2+7/2)=252

x.6=252

x=42

1: Thay \(x=\dfrac{1}{25}\) vào C, ta được:

\(C=\left(\dfrac{1}{5}+2\right):\left(\dfrac{1}{5}-3\right)=\dfrac{11}{5}:\dfrac{-14}{5}=-\dfrac{11}{14}\)

2: Để C=-2 thì \(\sqrt{x}+2=-2\left(\sqrt{x}-3\right)\)

\(\Leftrightarrow\sqrt{x}+2+2\sqrt{x}-6=0\)

\(\Leftrightarrow3\sqrt{x}=4\)

hay \(x=\dfrac{16}{9}\)

Để \(C=\dfrac{7}{5}\) thì \(\dfrac{\sqrt{x}+2}{\sqrt{x}-3}=\dfrac{7}{5}\)

\(\Leftrightarrow7\sqrt{x}-21=2\sqrt{x}+10\)

\(\Leftrightarrow5\sqrt{x}=31\)

hay \(x=\dfrac{961}{25}\)

Ta có : (x + 2) + (x + 5) + (x + 8) + ...... + (x + 32) = 198

<=> (x + x + x + ...... + x) + (2 + 5 + 8 + ....... + 32) = 198

<=> 11x + 187 = 198

=> 11x = 198 - 187

=> 11x = 11

=> x = 1

a . 

 \(x+x\times\frac{1}{3}\div\frac{2}{9}+x\div\frac{2}{7}=252\)

\(x+x\times\frac{3}{2}+x=252\times\frac{2}{7}\)

\(x+x\times\frac{3}{2}+x=72\)

\(x=72\div\frac{3}{2}-3x\)

\(x=48-3x\)

\(x=45\)

\(\left(x+2\right)+\left(x+5\right)+\left(x+8\right)+....\left(x+32=198\right)\)

1: =>x^2+4x-21=0

=>(x+7)(x-3)=0

=>x=3 hoặc x=-7

2: =>(2x-5-4)(2x-5+4)=0

=>(2x-9)(2x-1)=0

=>x=9/2 hoặc x=1/2

3: =>x^3-9x^2+27x-27-x^3+27+9(x^2+2x+1)=15

=>-9x^2+27x+9x^2+18x+9=15

=>18x=15-9-27=-21

=>x=-7/6

6: =>4x^2+4x+1-4x^2-16x-16=9

=>-12x-15=9

=>-12x=24

=>x=-2

7: =>x^2+6x+9-x^2-4x+32=1

=>2x+41=1

=>2x=-40

=>x=-20

x+x*\(\frac{1}{2}\):\(\frac{2}{9}\)+x:\(\frac{2}{7}\)=252

x+x*\(\frac{9}{4}\)+x*\(\frac{7}{2}\)=252

x*(1+\(\frac{9}{4}\)+\(\frac{7}{2}\))=252

x*\(\frac{27}{4}\)=252

x=252:\(\frac{27}{4}\)

x=\(\frac{112}{3}\)

Vậy x=\(\frac{112}{3}\)

Học tốt

\(x+x\times\frac{1}{2}\div\frac{2}{9}+x\div\frac{2}{7}=252\)

\(x\times1+x\times\frac{9}{4}+x\times\frac{7}{2}=252\)

\(x\times\left(1+\frac{9}{4}+\frac{7}{2}\right)=252\)

\(x\times\frac{17}{4}=252\)

\(x=252\div\frac{17}{4}\)

\(x=252\times\frac{4}{17}\)

\(x=\frac{1008}{17}\)

Chắc sai =]]

\(x+x×\frac{1}{3}:\frac{2}{9}+x×\frac{2}{7}=252\)

\(\Rightarrow x+x×\frac{1}{3}×\frac{9}{2}+x×\frac{7}{2}=252\)

\(x\left(1+\frac{1}{3}×\frac{9}{2}+\frac{7}{2}\right)=252\)

\(x×\frac{36}{6}=252\)

\(x×6=252\)

\(x=252:6\)

\(x=43\)

x+x.1/3:2/9+x:2/7=252

x+x.1/3.9/2+x.7/2=252

x(1+1/3+9/2+7/2)=252

x.36/6                 =252

=>x                     =252:6

=>x                     =42

Sửa 42→43 cho chị nha

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