a/ \(5x-\left(3x-\dfrac{1}{2}\right)=4\dfrac{1}{2}\)
\(\Leftrightarrow5x-3x+\dfrac{1}{2}=4\dfrac{1}{2}\)
\(\Leftrightarrow2x+\dfrac{1}{2}=4\dfrac{1}{2}\)
\(\Leftrightarrow2x=4\dfrac{1}{2}-\dfrac{1}{2}\)
\(\Leftrightarrow2x=3\dfrac{1}{2}\)
\(\Leftrightarrow x=\dfrac{7}{4}\)
Vậy .....
b/ \(\dfrac{x+8}{6}=\dfrac{5-x}{7}\)
\(\Leftrightarrow7\left(x+8\right)=6\left(5-x\right)\)
\(\Leftrightarrow7x+56=30-6x\)
\(\Leftrightarrow7x+6x=30-56\)
\(\Leftrightarrow13x=-26\)
\(\Leftrightarrow x=-2\)
Vây ....
c/ \(7\dfrac{1}{2}-\left|2x+1\right|=0,5\)
\(\Leftrightarrow\left|2x+1\right|=7\)
\(\Leftrightarrow\left[{}\begin{matrix}2x+1=7\\2x+1=-7\end{matrix}\right.\) \(\Leftrightarrow\left[{}\begin{matrix}x=3\\x=-4\end{matrix}\right.\)
Vậy ..
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