解二元一次方程2x-y-3=3 与3x+2y-8=0

2024-12-02 09:06:50
推荐回答(3个)
回答1:

2x-y-3=3
3x+2y-8=0

4x-2y=12
3x+2y=8

7x=20
x=20/7

40/7-y-3=3
y=6-40/7
y=2/7

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回答2:

2x-y=6①
3x+2y=8②
①*2+②
4x-2y+3x+2y=12+8
7x=20
x=20/7
y=40/7-6
y=2/7

回答3:

先移向 2x-y=3+3 ,2x-y=6 ,3x+2y=8
然后大括号{2x-y=6为1式,3x+2y=8为2式,将1式乘以2则为4x-2y=12,然后式1+式2,7x=20,x=20/7,将x=20/7代入式一,2×20/7-y=6,-y=6-40/7,-y=42/7-40/7,-y=2/7,y=-2/7