问题标题:
4[2x+y]-5[2x-y]=32[2x+y]+10[2x-y]=39
问题描述:

4[2x+y]-5[2x-y]=3

2[2x+y]+10[2x-y]=39

龚海里回答:
  8x+4y-10x+5y=3->9y-2x=3得:x=1.875   4x+2y+20x-10y=39->24x-8y=39y=0.75
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