整体代入法解{2(x-y)/3-x+y/4=-1;6(x+y)-4(2x-y)=16 必须快!二十分钟以内,设(x-y)=s,(x+y)=t 整体代入解

问题描述:

整体代入法解{2(x-y)/3-x+y/4=-1;6(x+y)-4(2x-y)=16 必须快!二十分钟以内,
设(x-y)=s,(x+y)=t 整体代入解

2(x-y)/3-(x+y)/4=-1.16(x+y)-4(2x-y)=16 .2由1式得8(x-y)-3(x+y)=-128x-8y-3x-3y=-125x-11y=-12.3由2式得6x+6y-8x+4y=16-2x+10y=16x-5y=-8.43式-4式*5得14y=28y=2将y=2代入4式得x-5*2=-8x=2所以x=2,y=2...