Prove:
#x^(log_10(y)-log_10(z))y^(log_10(z)-log_10(x))z^(log_10(x)-log_10(y))=1#
Use the base 10 logarithm on both sides:
#log_10(x^(log_10(y)-log_10(z))y^(log_10(z)-log_10(x))z^(log_10(x)-log_10(y)))=log_10(1)#
The right side becomes 0:
#log_10(x^(log_10(y)-log_10(z)))+log_10(y^(log_10(z)-log_10(x)))+log_10(z^(log_10(x)-log_10(y)))=0#
Use the property of logarithms #log_b(a^(c-d)) = log_b(a)(c-d)#
#log_10(x)(log_10(y)-log_10(z))+log_10(y)(log_10(z)-log_10(x))+log_10(z)(log_10(x)-log_10(y))=0#
Use the distributive property on all of the parenthesis:
#log_10(x)log_10(y)-log_10(x)log_10(z)+log_10(y)log_10(z)-log_10(y)log_10(x)+log_10(z)log_10(x)-log_10(z)log_10(y))=0#
Begin canceling terms:
#cancel(log_10(x)log_10(y))-log_10(x)log_10(z)+log_10(y)log_10(z)cancel(-log_10(y)log_10(x))+log_10(z)log_10(x)-log_10(z)log_10(y))=0#
#cancel(-log_10(x)log_10(z))+log_10(y)log_10(z)cancel(+log_10(z)log_10(x))-log_10(z)log_10(y))=0#
#cancel(+log_10(y)log_10(z))cancel(-log_10(z)log_10(y))=0#
#0 = 0#
Q.E.D.