已知:x/3=y/5=z/7,2x+y-z=8,求:3x+2y-z的值.
问题描述:
已知:
=x 3
=y 5
,2x+y-z=8,求:3x+2y-z的值. z 7
答
设
=x 3
=y 5
=k,则x=3k,y=5k,z=7k,z 7
又2x+y-z=8,则6k+5k-7k=8,k=2,
即x=6,y=10,z=14,所以3x+2y-z=3×6+2×10-14=24.