已知x+y-7z=0,且x-2y+5z=0(xyz≠0),求x+2y-z/-2x+y+12z的值

问题描述:

已知x+y-7z=0,且x-2y+5z=0(xyz≠0),求x+2y-z/-2x+y+12z的值

x+y-7z=0
x-2y+5z=0
推出X=3Y/4 Z=Y/4
把X、Z带入x+2y-z/-2x+y+12z
约分后得1 所以x+2y-z/-2x+y+12z的值为1