初二数学题2已知x/2=y/3=z/4,那么(x^
已知x/2=y/3=z/4,那么(x^-2y^+3z^)/(xy+2yz+3xz)=?
设x/2=y/3=z/4=k 则x=2k,y=3k,z=4k 原式=[4k^-2(3k)^+3(4k)^]/(2k*3k+2*3k*4k+3*2k*4k) k^约掉 17/27