题目解下列方程组：(1){2x−y=−5,3x+4y=9.(1)\left\{\begin{array}{l}2x-y=-5,\\ 3x+4y=9.\\\end{array}\right.(1){2x−y=−5,3x+4y=9.(2){3(x+y)−4(x−y)=4,x+y2+x−y6=1.(2)\left\{\begin{array}{l}3(x+y)-4(x-y)=4,\\ \dfrac{x+y}{2}+\dfrac{x-y}{6}=1.\\\end{array}\right.(2){3(x+y)−4(x−y)=4,2x+y+6x−y=1.知识点：解二元一次方程组——加减消元法章节：方程与不等式 / 二元一次方程组
