已知x-4y=0,z=5x(x不等于0),求代数式x-14y+3z/x+y+z的值

问题描述:

已知x-4y=0,z=5x(x不等于0),求代数式x-14y+3z/x+y+z的值

x=4y
z=5x=20y
(x-14y+3z)/(x+y+z)
=(4y-14y+20y)/(4y+y+20y)
=10y/25y
=2/5
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