\(a,\frac{3}{4}+\frac{1}{4}:x=\frac{2}{5}\)
\(\Leftrightarrow\frac{1}{4}:x=\frac{2}{5}-\frac{3}{4}\)
\(\Leftrightarrow\frac{1}{4}:x=\frac{8}{20}-\frac{15}{20}\)
\(\Leftrightarrow\frac{1}{4}:x=\frac{-7}{20}\)
\(\Leftrightarrow x=\frac{1}{4}.\frac{20}{-7}\)
\(\Leftrightarrow x=\frac{20}{-28}\)
\(b,|x-2,5|=1,5\)
\(\Leftrightarrow\orbr{\begin{cases}x-2,5=1,5\\x-2,5=-1,5\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x=1,5+2,5\\x=-1,5+2,5\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x=3\\x=1\end{cases}}\)
\(\frac{3}{4}+\frac{1}{4}:x=\frac{2}{5}\) \(/x-2.5/=1.5\)
\(\frac{1}{4}:x=\frac{2}{5}-\frac{3}{4}\) \(\Rightarrow x-2.5=1.5;x-2.5=-1.5\)
\(\frac{1}{4}:x=-\frac{7}{20}\) \(TH1:x-2.5=1.5\Rightarrow x=4\)
\(x=\frac{1}{4}:-\frac{7}{20}\) \(TH2:x-2.5=-1.5\Rightarrow1\)
\(x=-\frac{5}{7}\)
a)\(\frac{3}{4}+\frac{1}{4}:x=\frac{2}{5}\)
\(\frac{1}{4}:x=\frac{2}{5}-\frac{3}{4}\)
\(\frac{1}{4}:x=\frac{-7}{20}\)
\(x=\frac{-5}{7}\)
b) \(\left|x-2,5\right|=1,5\)
\(\Leftrightarrow\orbr{\begin{cases}x-2,5=-1,5\\x-2,5=1,5\end{cases}\Leftrightarrow\orbr{\begin{cases}x=1\\x=4\end{cases}}}\)
Vậy : \(x\in\left\{1;4\right\}\)
a.\(\frac{3}{4}+\frac{1}{4}:x=\frac{2}{5}\)
\(\frac{1}{4}:x=\frac{-7}{20}\)
\(x=-\frac{5}{7}\)
b.\(\left|x-2,5\right|=1,5\Leftrightarrow\orbr{\begin{cases}x-2,5=1,5\\x-2,5=-1,5\end{cases}\Leftrightarrow\orbr{\begin{cases}x=4\\x=1\end{cases}}}\)
