x/17 + 19/34 = 2 1/2

x/17 + 19/34 = 5/2

x/17             = 5/2 - 19/34

x/17             = 33/17

Vậy x = 33

 x/17 + 19/34 =2 1/2

x/17 + 19/34 =5/2

x/17              =  5/2 - 19/34

x/17              =  33/17

Vậy x = 17 

\(\dfrac{x}{17}+\dfrac{19}{34}=2\dfrac{1}{2}\)

\(\Rightarrow\dfrac{x}{17}+\dfrac{19}{24}=\dfrac{5}{2}\)

\(\Rightarrow\dfrac{x}{17}=\dfrac{33}{17}\Rightarrow x=33\)

\(\dfrac{15}{34}+\dfrac{7}{21}+\dfrac{19}{34}-1\dfrac{15}{17}+\dfrac{2}{3}\)

= \(\left(\dfrac{15}{34}+\dfrac{19}{34}\right)+\left(\dfrac{7}{21}+\dfrac{2}{3}\right)-1\dfrac{15}{17}\)

= \(1+\left(\dfrac{7}{21}+\dfrac{14}{21}\right)-1\dfrac{15}{17}\)

= \(1+1-1\dfrac{15}{17}\)

= \(2-1\dfrac{15}{17}\)

= \(\dfrac{2}{17}\)

= 100% luôn

\(\dfrac{15}{34}+\dfrac{7}{21}+\dfrac{19}{34}-\dfrac{32}{17}+\dfrac{2}{3}\) 

\(=\left(\dfrac{15}{34}+\dfrac{19}{34}\right)+\dfrac{7}{21}+\dfrac{-32}{17}+\dfrac{2}{3}\) 

\(=1+\dfrac{1}{3}+\dfrac{-32}{17}+\dfrac{2}{3}\) 

\(=1+\left(\dfrac{1}{3}+\dfrac{2}{3}\right)+\dfrac{-32}{17}\) 

\(=1+1+\dfrac{-32}{17}\) 

\(2+\dfrac{-32}{17}=\dfrac{2}{17}\)

\(\dfrac{15}{34}-\dfrac{7}{21}+\dfrac{19}{34}-\dfrac{15}{17}-\dfrac{2}{3}\)

\(=\left(\dfrac{15}{34}+\dfrac{19}{34}\right)-\left(\dfrac{7}{21}+\dfrac{2}{3}\right)-\dfrac{15}{17}\)

\(=1-\left(\dfrac{7}{21}+\dfrac{14}{21}\right)-\dfrac{15}{17}\)

\(=1-1-\dfrac{15}{17}\)

\(=-\dfrac{15}{17}\)

x/17=5/2-19/34

x/17=33/17

x=33/17*17

x=33

 h mk nha