x=13:3

hình như sai đề bài r bn

Mk định ko tl nhưng thấy ''đề sai'' mk nghĩ bn sai chứ để x là PS ko sai 

\(\frac{-2}{3}+\frac{x}{5}=\frac{1}{5}\)

\(\frac{-10}{15}+\frac{3x}{15}=\frac{3}{15}\)

\(-10+3x=3\)

\(3x=3-\left(-10\right)\Leftrightarrow3x=13\Leftrightarrow x=\frac{13}{3}\)

x/5=1/5+2/3

x/5=13/15

3x/15=13/15

3x=13

=>x=13/3

\(a)x+30\%x=-1,31\)

\(\Leftrightarrow x+\frac{3x}{10}=-1,31\)

\(\Leftrightarrow10x+3x=-13,1\)

\(\Leftrightarrow13x=-13,1\Leftrightarrow x=-\frac{131}{130}\)

\(b)\left(x-\frac{1}{2}\right):\frac{1}{3}+\frac{5}{7}=9\frac{5}{7}\)

\(\Leftrightarrow\frac{2x-1}{2}.3+\frac{5}{7}=\frac{68}{7}\)

\(\Leftrightarrow\frac{6x-3}{2}=\frac{63}{7}\)

\(\Leftrightarrow\frac{6x-3}{2}=9\)

\(\Leftrightarrow6x-3=18\)

\(\Leftrightarrow x=\frac{7}{2}\)

\(c)\frac{1}{2}x-\frac{3}{4}=\frac{14}{9}.\frac{3}{7}\)

\(\Leftrightarrow\frac{x}{2}-\frac{3}{4}=\frac{2}{3}\)

\(\Leftrightarrow\frac{x}{2}=\frac{17}{12}\)

\(\Leftrightarrow12x=34\Leftrightarrow x=\frac{17}{6}\)

đé* biết ok

=> (x+2) 2 = (2x+1) 0,5

2x + 4 = x+0,5

=> x= -3,5

Ta có:  $\frac{x+2}{0,5}=\frac{2x+1}{2}$

=>2*(x+2)=0,5*(2x+1)

=>2x+4=x+0,5

=>2x-x=0,5-4

=>x=-3,5

2/5 ; 12/25 ; 14/27 ; 5/9 nhé!

2/5<12/25<14/27<5/9

1)

a)

\(\frac{-5}{6}.\frac{120}{25}< x< \frac{-7}{15}.\frac{9}{14}\)

\(\frac{-1}{1}.\frac{20}{5}< x< \frac{-1}{5}.\frac{3}{2}\)

\(\frac{-20}{5}< x< \frac{-3}{10}\)

\(\frac{-40}{10}< x< \frac{-3}{10}\)

\(\Rightarrow Z\in\left\{-4;-5;-6;-7;-8;-9;-10;...;-39\right\}\)

\(\left(\frac{-5}{3}\right)^3< x< \frac{-24}{35}.\frac{-5}{6}\)

\(\frac{25}{3}< x< \frac{-4}{7}.\frac{1}{1}\)

\(\frac{-25}{3}< x< \frac{-4}{7}\)

\(\frac{-175}{21}< x< \frac{-12}{21}\)

\(\Rightarrow Z\in\left\{-13;-14;-15;-16;...;-174\right\}\)

2)

a)

\(\left(\frac{9}{10}-\frac{15}{16}\right).\left(\frac{5}{12}-\frac{11}{15}-\frac{7}{20}\right)\)

\(=\left(\frac{72}{80}-\frac{75}{80}\right).\left(\frac{25}{60}-\frac{44}{60}-\frac{21}{60}\right)\)

\(=\frac{-3}{80}.\frac{-40}{60}\)

\(=\frac{-1}{-2}.\frac{-1}{-20}\)

\(=\frac{1}{40}\)

(2x-1/3)^2 = 1/16

=> 2x-1/3 = 1/4 hoặc 2x-1/3=-1/4

=> x=7/24 hoặc 1/24

Vậy .............

Tk mk nha

\(\left(2x-\frac{1}{3}\right)^2=\frac{1}{16}\)

\(\left(2x-\frac{1}{3}\right)^2=\left(\frac{1}{4}\right)^2hay\left(-\frac{1}{4}\right)^2\)

\(\Rightarrow\orbr{\begin{cases}2x-\frac{1}{3}=\frac{1}{4}\Rightarrow2x=\frac{1}{4}+\frac{1}{3}=\frac{7}{12}\Rightarrow x=\frac{7}{24}\\2x-\frac{1}{3}=-\frac{1}{4}\Rightarrow2x=-\frac{1}{4}+\frac{1}{3}=\frac{1}{12}\Rightarrow x=\frac{1}{24}\end{cases}}\)

Vậy ..

học tốt 
 

ta có  \(\left(2x-\frac{1}{3}\right)^2=\frac{1}{16}\)

\(TH1\Rightarrow\left(2x-\frac{1}{3}\right)^2=\left(\frac{1}{4}\right)^2\)

\(\Leftrightarrow2x-\frac{1}{3}=\frac{1}{4}\Leftrightarrow2x=\frac{1}{4}+\frac{1}{3}\)

\(\Leftrightarrow2x=\frac{7}{12}\Rightarrow x=\frac{7}{12}:2=\frac{7}{24}\)

\(TH2\Rightarrow2x-\frac{1}{3}=-\frac{1}{4}\)

\(\Leftrightarrow2x=-\frac{1}{4}+\frac{1}{3}\)

\(\Leftrightarrow2x=\frac{1}{12}\Rightarrow x=\frac{1}{24}\)

Vậy \(x\in\left\{\frac{7}{24};\frac{1}{24}\right\}\)thì thỏa mãn đề bài