已知2x+5y+4z=15,7x+y+3z=14,求4x+y+2z=m

来源：百度知道编辑：UC知道时间：2024/06/26 03:50:55

一式乘以1/11 二式乘以6/11 相加即得结果
M=9

2x+5y+4z=15,.......(1)
7x+y+3z=14.........(2)
(2)*4-(1)*3,得
22x-11y=11
2x-y=1
y=2x-1
(2)*5-(1),得
33x+11z=55
3x+z=5
z=5-3x
所以
m=4x+y+2z
=4x+(2x-1)+2(5-3x)
=4x+2x-1+10-6x
=9

m等于9

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