[tex]\it \dfrac{a}{b}=\dfrac{3}{4} \Rightarrow \dfrac{a-b}{b}=\dfrac{3-4}{4} \Rightarrow \dfrac{11}{b}=\dfrac{-1}{4} \Rightarrow b=\dfrac{11\cdot4}{-1}=-44\\ \\ \\ \dfrac{a}{-44}=\dfrac{3}{4} \Rightarrow a=\dfrac{-44\cdot3}{4} =-33 \\ \\ \\ \dfrac{a}{b}=\dfrac{-33}{-44}=\dfrac{3}{4}[/tex]
