2·㏒b(x)=㏒a(x)+㏒c(x) <=> 2/㏒x(b)=1/㏒x(a)+1/㏒x(c) <=>
2/㏒x(b)=㏒x(a)+㏒x(c) /㏒x(a)·㏒x(c) <=>
2/㏒x(b)=㏒x(ac) /㏒x(a)·㏒x(c) <=> ㏒x(b)·㏒x(ac)=2·㏒x(a)·㏒x(c) <=>
㏒x(b)·㏒x(a)+㏒x(b)+㏒x(c)=㏒x(a)·㏒x(c)+㏒x(a)·㏒x(c) <=>
㏒x(b)=㏒x(c)=㏒x(a) <=> b=c=a => ㏒a(b)=㏒a(a)=1 => c²=ac <=> c²=c² <=>
(c-c)·(c+c)=0 <=> 0=0 ,care este adevarat => c²=(ac) la puterea ㏒a(b) .
