\(a)\) \(y+30\%=\dfrac{-1}{3}\)
\(\Rightarrow y+\dfrac{3}{10}=\dfrac{-1}{3}\)
\(\Rightarrow y=\dfrac{-19}{30}\)
Vậy ...
\(b)\) \(y-25\%y=\dfrac{1}{2}\)
\(\Rightarrow1y-\dfrac{1}{4}y=\dfrac{1}{2}\)
\(\Rightarrow y\left(1-\dfrac{1}{4}\right)=\dfrac{1}{2}\)
\(\Rightarrow y\dfrac{3}{4}=\dfrac{1}{2}\)
\(\Rightarrow y=\dfrac{2}{3}\)
Vậy .....
a, \(y+30\%=-1,3\)
\(\Rightarrow y=-\dfrac{13}{10}-\dfrac{3}{10}\)
\(\Rightarrow y=\dfrac{-8}{10}\)
b, \(y-25\%y=\dfrac{1}{2}\)
\(\Rightarrow y\left(1-\dfrac{1}{4}\right)=\dfrac{1}{2}\)
\(\Rightarrow\dfrac{3}{4}y=\dfrac{1}{2}\)
\(\Rightarrow y=\dfrac{1}{2}:\dfrac{3}{4}\)
\(\Rightarrow y=\dfrac{2}{3}\)
