Question

若方程组2x+3y=43x+2y=2m-3的解满足x+y=1/5则m=多少

要过程

Answer 1

2x+3y=4
3x+2y=2m-3
5x+5y=2m+1=1
m=0

Answer 2

2x+3y=43①
x+2y=2m-3②
①-②
x+y=43-2m+3
x+y=46-2m=0.2
2m=46-0.2=45.8
m=22.9

0.0
原来题目是这样的啊
怎么不给打个回车~~
2x+3y=4①
3x+2y=2m-3②
①+②
5x+5y=2m+1
x+y=1/5
5x+5y=1
2m+1=1
m=0

Answer 3

2x+3y=4 6x+9y=12 A
3x+2y=2m-3 6x+4y=4m-6 B
A-B得5y=18-4m
y=(18-4m)/5
代入A得：2x+3(18-4m)/5=4
2x+(54-12m)/5=4
10x+54-12m-20=0
10x=12m-34
x=(6m-17)/5
x+y=1/5
(6m-17)/5-(18-4m)/5=1/5
6m-17-(18-4m)=1
10m-35=1
m=3.6