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3(x+y)-2(x-y)=95(x+y)+2(x-y)=-1用加减消元法解3(x+y)-2(x-y)=95(x+y)+2(x-y)=-1

题目详情
3(x+y)-2(x-y)=9 5(x+y)+2(x-y)=-1 用加减消元法解
3(x+y)-2(x-y)=9 5(x+y)+2(x-y)=-1
▼优质解答
答案和解析
3(x+y)-2(x-y)=9 (1)
5(x+y)+2(x-y)=-1 (2)
(1)+(2)得:
x+y=1 (3)
(1)*5-(2)*3得:
x-y=-3 (4)
(3)+(4)得:
2x=-2
x=-1
代入(3)得:
y=1-x=2
所以,方程组得解是:x=-1;y=2