2x-y-2=0 4x-3y-8=0 用加减消元法做
问题描述：
2x-y-2=0 4x-3y-8=0 用加减消元法做
答
（1）*2得4x-2y-4=0 (2)-(1)得-y-4=0
-y=4
y=-4
x=-1
答
y=-4.x=-1
答
2x-y-2=0
2x-y=2①
4x-3y-8=0
4x-3y=8②
①×2
4x-2y=4③
③-②
y=-4
x=-2
答
2x - y - 2 = 0 ……①
4x - 3y - 8 = 0……②
② - ①×2得：y = - 4……③
③代入①得：x = -2