已知x+y+z=0,求ax+ay+az-bx-by-bz的值
问题描述:
已知x+y+z=0,求ax+ay+az-bx-by-bz的值
答
ax+ay+az-bx-by-bz
=a(x+y+z)-b(x+y+z)
=(a-b)(x+y+z)
=(a-b)×0
=0