[tex]\it 7(x-14)=4(x+7) \Rightarrow \dfrac{x-14}{x+7}=\dfrac{4}{7} \Rightarrow \dfrac{x-14-x-7}{x+7}=\dfrac{4-7}{7} \Rightarrow \\ \\ \\ \Rightarrow \dfrac{-21}{x+7}=\dfrac{-3}{7} \Rightarrow- \dfrac{x+7}{21}=-\dfrac{^{7)}7}{\ 3} \Rightarrow -\dfrac{x+7}{21}=-\dfrac{49}{21} \Rightarrow x+7=49 \Rightarrow \\ \\ \\ \Rightarrow x=49-7 \Rightarrow x=42[/tex]
