\(\dfrac{29}{30}-\left(\dfrac{13}{30}+x\right)=\dfrac{7}{69}\)
\(\Leftrightarrow\dfrac{13}{23}+x=\dfrac{29}{30}-\dfrac{7}{69}\)
\(\Leftrightarrow\dfrac{13}{23}+x=\dfrac{199}{230}\)
\(\Leftrightarrow x=\dfrac{199}{230}-\dfrac{13}{23}\)
\(\Leftrightarrow x=\dfrac{69}{230}\)