问题 填空题
已知
x
3
=
y
4
=
z
5
,且4x-5y+2z=10,则2x-5y+z的值等于______.
答案

x
3
=
y
4
=
z
5
=t,

则x=3t,y=4t,z=5t,

代入4x-5y+2z=10中,得

12t-20t+10t=10,

解得t=5,

∴2x-5y+z=6t-20t+5t,

=-9t,

=-45.

故本题答案为:-45.

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