趣味的数学-298
x≠y≠z，x(y-z)、y(z-x)和z(x-y)组成一个等比数列，其公比是r，求r满足以下哪个等式？
A】r^2 - r +1 = 0
B】r^4 + r^2 - 1 = 0
C】r^2 + r +1 = 0
D】(r+1)^4 + r = 0
E】(r-1)^4 + r = 0
