已知4x-3y-6z=0和x+2y-7z=0能组成一个方程组,

4x-3y-6z=0---(1) x+2y-7z=0---(2) 整理(1)(2) 4x-3y=6z---(3) x+2y=7z---(4) (3)*2+(4)*3 11x=33z x=3z (4)*4-(3) 11y=22z y=2z 3xy+yz+4zx ————————————— =(18z^2+2z^2+12z^2)/(18z^2+4z^2+8z^2)=16/...