解方程组 1.3(x+y)-4(x-y)=4,x+y/2 + x-y/6 =1 2.5x+4y+z=0,3x+y-4z=11,x+y+z=-2
问题描述：
解方程组 1.3(x+y)-4(x-y)=4,x+y/2 + x-y/6 =1 2.5x+4y+z=0,3x+y-4z=11,x+y+z=-2
答
1.3(x+y)-4(x-y)=4,(1)x+y/2 + x-y/6 =1 (2)由(1),得:x=7y-4,代入(2),得14y-y/3=9,y=27/41,x=25/412.5x+4y+z=0,(1)3x+y-4z=11,(2) x+y+z=-2 (3)4(1)+(2):23x+17y=11 (4)(1)-(3):4x+3y=2 (5)3(4)-17(5):x=-1由(5),y=2...