Question

已知；4x-3y-6z=0,x+2y-7y=0(xyz不等于0),求2x+3y+6z/x+5y+7z的值

Answer 1

令z=1代入4x-3y-6z=0,x+2y-7y=0得

4x-3y-6=0

x+2y-7=0

y=2,x=3

代入得

(2x+3y+6z)/(x+5y+7z)=(6+6+6)/(3+10+7)=9/10