a) 67845 – y = 29361

y = 67845 – 29361

y = 38484

a) 67845 – y = 29361

y = 678445 - 29361

y = 649034

 b) y : 208 = 317

y = 317 x 208

y = 65936

a) 67845 – y = 29361

                  y = 678445 - 29361

                  y = 649034

 b) y : 208 = 317

     y           = 317 x 208

     y           = 65936

a) 67 845 - y = 29 361

                   y = 67 845 - 29 361

                   y = 649 034

b) y : 208 = 317

              y = 317 x 208

              y = 65 936

help

8344935

= 8344935

=217 dư 141

tick cho mình nha

( x + 1259 ) x 5 = 67845

( x + 1259 )      = 67845 : 5

( x + 1259 )      = 13569

x                       = 13569 - 1259

x                       = 12310

Mình nghĩ đề bài sai bạn ạ

tk nhé

ai k mình mình k lại

(x+1259)x5=12345+45691

(x+1259)x5=58036

x+1259      =58036:5

x+1259      =11607,2

               x=11607,2-1259

               x=10348,2

a,3/1-3/4=21/4-3/4=18/4=9/4

d,217,46

a) \(\dfrac{5}{y}=\dfrac{1}{2}\)

\(y=\dfrac{5\times2}{1}=10\)

b) \(\dfrac{42}{25}:\dfrac{y}{5}=\dfrac{6}{5}\)

\(\dfrac{y}{5}=\dfrac{42}{25}:\dfrac{6}{5}\)

\(\dfrac{y}{5}=\dfrac{7}{5}\)

\(y=7\)

\(\dfrac{5}{y}=\dfrac{1}{2}\\ =>y=5.2:1=10\)

\(\dfrac{42}{25}:\dfrac{y}{5}=\dfrac{6}{5}\\ =>\dfrac{y}{5}=\dfrac{42}{25}:\dfrac{6}{5}=\dfrac{42}{25}.\dfrac{5}{6}=\dfrac{7}{5}\\ =>y=\dfrac{7}{5}.5=7\)

a) \(\dfrac{5}{y}=\dfrac{1}{2}\)

\(\Rightarrow y=5\cdot2:1=10\)

b) \(\dfrac{42}{25}:\dfrac{y}{5}=\dfrac{6}{5}\)

\(\dfrac{y}{5}=\dfrac{42}{25}:\dfrac{6}{5}=\dfrac{7}{5}\)

\(\dfrac{y}{5}=\dfrac{7}{5}\)

\(\Rightarrow y=7\)

Bài 5 :

a) \(\dfrac{y}{4}=\dfrac{9}{y}\)

\(\Rightarrow y^2=36\left(y\ne0\right)\)

\(\Rightarrow y=\pm6\)

b) \(\dfrac{y+7}{20}=\dfrac{5}{y+7}\left(y\ne-7\right)\)

\(\Rightarrow\left(y+7\right)^2=100=10^2\)

\(\Rightarrow\left[{}\begin{matrix}y+7=10\\y+7=-10\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}y=3\\y=-17\end{matrix}\right.\)

c) \(\dfrac{4-5y}{3}=\dfrac{y+2}{5}\)

\(\Rightarrow5\left(4-5y\right)=3\left(y+2\right)\)

\(\Rightarrow20-25y=3y+6\)

\(\Rightarrow28y=14\)

\(\Rightarrow y=\dfrac{14}{28}=\dfrac{1}{2}\)

Bài 4 :

\(\dfrac{a}{5}=\dfrac{b}{7}=\dfrac{c}{10}\)

\(\Rightarrow\dfrac{2a}{10}=\dfrac{3b}{21}=\dfrac{4c}{40}=\dfrac{2a+3b-4c}{10+21-40}=\dfrac{81}{-9}=-9\)

\(\Rightarrow\left\{{}\begin{matrix}a=-9.5=-45\\b=-9.7=-63\\c=-9.10=-90\end{matrix}\right.\)

Đính chính Bài 4 :

\(...\dfrac{2a+3b-4c}{10+21-40}=\dfrac{-81}{-9}=9\)

\(\Rightarrow\left\{{}\begin{matrix}a=9.4=36\\b=9.7=63\\c=9.10=90\end{matrix}\right.\)