Maths Question ask by junior secondary student

Choose x = y = z = 1,
L.H.S = 1 = R.H.S.

Theredore, if x,y and n are both nature number,
z can be nature number

2008-03-24 14:12:47 補充：
any real number(inculding natrue number) n satisfy the above proof

x^(-n)*y^(-n)=z^(-n)
(xy)^n=z^n
xy=z
if x,y and n are natural number, then z is also a natural number