已知x-4y-5z=0,-3x+y+4z=0(xyz≠0)则xy⼀z^2=

2025-04-30 21:43:21
推荐回答(1个)
回答1:

x-4y-5z=0①,-3x+y+4z=0②
解:①×3+②得:-11y-11z=0解得y=-z
把y=-z代入①得:x+4z-5z=0解得x=z
所以xy/z^2=z×(-z)/z²=-z²/z²=-1