Giải các hệ phương trình :
a. \(\left\{{}\begin{matrix}2x-3y=1\\x+2y=3\end{matrix}\right.\)
b. \(\left\{{}\begin{matrix}2x+4y=5\\4x-2y=2\end{matrix}\right.\)
c. \(\left\{{}\begin{matrix}\dfrac{2}{3}x+\dfrac{1}{2}y=\dfrac{2}{3}\\\dfrac{1}{3}x-\dfrac{3}{4}y=\dfrac{1}{2}\end{matrix}\right.\)
d. \(\left\{{}\begin{matrix}0,3x-0,2y=0,5\\0,5x+0,4y=1,2\end{matrix}\right.\)