问题补充:
初一数学:若x-3=y-2=z-1,求x方+y方+z方-xy-yz-zx的值 过程
答案:
x-3=y-2=z-1=k
x=3+ky=2+kz=1+kx方+y方+z方-xy-yz-zx
=2(x方+y方+z方-xy-yz-zx)/2
=(x-y)^2+(y-z)^2+(x-z)^2/2
=(1+1+4)/2
=3
时间:2021-07-09 11:19:40
初一数学:若x-3=y-2=z-1,求x方+y方+z方-xy-yz-zx的值 过程
x-3=y-2=z-1=k
x=3+ky=2+kz=1+kx方+y方+z方-xy-yz-zx
=2(x方+y方+z方-xy-yz-zx)/2
=(x-y)^2+(y-z)^2+(x-z)^2/2
=(1+1+4)/2
=3
4x-2y+z=7 2x-y-3z=28 x+y-2z=13要过程
2020-03-10