a. \(y+30\%y=-1,3\)

\(=>y.\left(1+30\%\right)=-1,3\)

\(=>y.\left(1+\dfrac{3}{10}\right)=-1,3\)

\(=>y.\dfrac{13}{10}=\dfrac{-13}{10}\)

\(=>y=-1\)

b.\(y-25\%y=\dfrac{1}{2}\)

\(=>y.\left(1-25\%\right)=\dfrac{1}{2}\)

\(=>y.\left(1-\dfrac{1}{4}\right)=\dfrac{1}{2}\)

\(=>y.\dfrac{3}{4}=\dfrac{1}{2}\)

\(=>y=\dfrac{1}{2}.\dfrac{4}{3}\)

\(=>y=\dfrac{2}{3}\)

c.\(3\dfrac{1}{3}y+16\dfrac{3}{4}=-13,25\)

\(=>\dfrac{10}{3}y+\dfrac{67}{4}=\dfrac{-53}{4}\)

\(=>\dfrac{10}{3}y=\dfrac{-53-67}{4}\)

\(=>\dfrac{10}{3}y=\dfrac{-120}{4}\)

\(=>\dfrac{10}{3}y=-30\)

\(=>y=-30.\dfrac{3}{10}\)

\(=>y=-9\)

tick cho mk nha

k hiểu chỗ nào thì hỏi mk

a, y + 30%y = -1,3

 1.y + 30/100y = -13/10

 1.y + 3/10y  = -13/10

(1 + 3/10). y = -13/10

13/10 .y = -13/10

           y = -13/10 : 13/10

           y = -13/10 . 10/13

           y = -1

b, y - 25%y = 1/2

   1.y - 25/100.y = 1/2

   1.y - 1/4.y = 1/2

   (1 - 1/4) y = 1/2

    3/4 .y = 1/2

           y = 1/2 : 3/4

           y = 1/2 . 4/3

           y = 2/3

câu c mik chưa nghĩ ra

a)\(y+30\%y=-1,3\Rightarrow y+\frac{3}{10}y=-1,3\Rightarrow y\left(1+\frac{3}{10}\right)=-1,3\Rightarrow y\times1,3\)\(=-1,3\Rightarrow y=-1\)

b)\(y-25\%y=\frac{1}{2}\Rightarrow y-\frac{1}{4}y=\frac{1}{2}\Rightarrow y\left(1-\frac{1}{4}\right)=\frac{1}{2}\Rightarrow y\times\frac{3}{4}=\frac{1}{2}\Rightarrow y=\frac{1}{2}:\frac{3}{4}\Rightarrow y=\frac{2}{3}\)

c)\(3\frac{1}{3}y+16\frac{3}{4}=13,25\Rightarrow\frac{10}{3}y+\frac{67}{4}=\frac{53}{4}\Rightarrow\frac{10}{3}y=\frac{53}{4}-\frac{67}{4}\Rightarrow\frac{10}{3}y=\frac{-7}{2}\Rightarrow y=\frac{-21}{20}\)

-21/20

21/112

a) ta có :     y + 30/100y = -1,3

           hay       y(1+ 3/10)    = - 13/10

                       y.13/10 = -13/10

                       y= -13/10:13/10

                       y= -1

b)       y - 25/100y=1/2

hay    y(1-1/4)=1/2

         y.3/4 = 1/2

         y=2/3

c)    10/3y + 16,75 = -13,25

       10/3y= -13,25 - 16,75

       10/3y= -30

             y= - 30:10/3

             y= -9

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