咯X/3=y/4=z/5,且3x-2y+z=18.求z+5y-3z的值.

问题描述:

咯X/3=y/4=z/5,且3x-2y+z=18.求z+5y-3z的值.

x=3z/5
y=4z/5
3x-2y+z=18
3*3z/5-2*4/z/5+z=18
9z/5=18
z=10
x=3z/5=6
y=4z/5=8
z+5y-3z
=6+5*8-3*10
=16