\(\dfrac{1}{2x+7}=\dfrac{3}{4}\)
\(\Leftrightarrow1.4=\left(2x+7\right).3\)
\(\Leftrightarrow4=6x+21\)
\(\Leftrightarrow-6x=21-4\)
\(\Leftrightarrow-6x=17\)
\(\Leftrightarrow-6x=17:\left(-6\right)\)
\(\Leftrightarrow x=\dfrac{-17}{6}\)
Giải.
Ta có : \(\dfrac{1}{2x+7}=\dfrac{3}{4}\)
\(\Leftrightarrow3\left(2x+7\right)=1.4\)
\(\Leftrightarrow6x+21=4\)
\(\Leftrightarrow6x=-17\Leftrightarrow x=\dfrac{-17}{6}\)
Vậy \(x=\dfrac{-17}{6}\)
tik mik nha !!!
\(\dfrac{1}{2x+7}=\dfrac{3}{4}\Leftrightarrow3\left(2x+7\right)=4\Leftrightarrow6x+21=4\)
\(\Leftrightarrow6x=4-21=-17\Leftrightarrow x=\dfrac{-17}{6}\) vậy \(x=\dfrac{-17}{6}\)
