{2x-3y=8{3x+7y=0.5 并且用代入法解
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{2x-3y=8{3x+7y=0.5 并且用代入法解
{2x-3y=8{3x+7y=0.5 并且用代入法解
{2x-3y=8{3x+7y=0.5 并且用代入法解
由题意得x=4+1.5y;代入后式得
3*(4+1.5y)+7y=0.5
12+4.5y+7y=0.5
11.5y=-11.5
y=-1;x=4+1.5*(-1)=2.5
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