1.x-y-z=1 2x+y-3z=4 3x-2y-z=-1 2.a+0.5b=c 0.5a-b-c=1 3a+b=-2

题目

1.x-y-z=1 2x+y-3z=4 3x-2y-z=-1 2.a+0.5b=c 0.5a-b-c=1 3a+b=-2
1.
x-y-z=1
2x+y-3z=4
3x-2y-z=-1
2.
a+0.5b=c
0.5a-b-c=1
3a+b=-2

答案

1.x-y-z=1.① ⑥ ⑦2x+y-3z=4..②3x-2y-z=-1.③③-① 2x-y=-2④③*3-② 7x-7y=-7,x-y=-1⑤④-⑤ x=-1, y=0.代入① z=-2x=-1y=0z=-2 2.a+0.5b=c ①0.5a-b-c=1 ②3a+b=-2 ③②-① ...