作业帮3x+7y+z=5 ,4x+10y+z=6 ,x+y+z=以后遇到这种题怎么办?
来源：学生作业帮助网 编辑：作业帮 时间：2024/05/12 05:21:22
3x+7y+z=5 ,4x+10y+z=6 ,x+y+z=以后遇到这种题怎么办?
3x+7y+z=5 ,4x+10y+z=6 ,x+y+z=
以后遇到这种题怎么办?
3x+7y+z=5 ,4x+10y+z=6 ,x+y+z=以后遇到这种题怎么办?
x+y+z=A(3x+7y+z)+B(4x+10y+z) 易知3A+4B=1,7A+10B=1,A+B=1,解得A=3,B=-2,所以原式=3*5-2*6=3,以后也是这样做就好了!给分吧!
a*(3x+7y+z)-b*(4x+10y+z)=x+y+z;
解得：a=3 b=2;
则x+y+z=3*(3x+7y+z)-2*(4x+10y+z)=3;
x+y+z=3把x z都用y来代替，全部换成一个再解
3x+7y+z=5..........(1)
4x+10y+z=3...........(2)
(1)*3-(2)*2得
x+y+z=15-6=9
所以x+y+z=9
3x+7y+z=5①
4x+10y+z=6②
②-①得x+3y=1
①X4-②X3得-2y+z=2
两式相加得x+y+z=3
若3x+7y+z=5,4x+10y+z=3,则x+y+z=?
已知x、y、z满足{3x+7y+z=5 ,求x+y+z的值 {4x+10y+z=3
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x+y-z=3 y+z-x=5 z+x-y=7 求x,y,z
(4x-2y-z)-{5x-[8y-2z-(x+y)]-2(3y-10z)}=?好难啊
2x+5y+4z=6,3x+y-7z=-4,x+y-z=?
{2x+3y-4z=-5 x+y+z=6 x-y+3z=10
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