b: Tọa độ giao điểm là:
\(\left\{{}\begin{matrix}2x-5=\dfrac{1}{2}x\\y=2x-5\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}\dfrac{3}{2}x=5\\y=2x-5\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=\dfrac{10}{3}\\y=2\cdot\dfrac{10}{3}-5=\dfrac{20}{3}-\dfrac{15}{3}=\dfrac{5}{3}\end{matrix}\right.\)