若x/3=y/4=z/5,则(xy+yz=xz)/(xx+yy+zz)的值为

Question

若x/3=y/4=z/5,则(xy+yz=xz)/(xx+yy+zz)的值为

Answer 1

令x/3=y/4=z/5=k；
则x=3k,y=4k,z=5k;
(xy+yz+xz)/(xx+yy+zz)=(3k*4k+4k*5k+3k*5k)/(3k*3k+4k*4k+5k*5k)=(12+20+15)/(9+16+25)=47/50