To prove: [x−bxa]a−b.[x−cxb]b−c.[x−axc]c−a=1
Taking LHS:
[x−bxa]a−b.[x−cxb]b−c.[x−axc]c−a=[x−b(a−b)xa(a−b)].[x−c(b−c)xb(b−c)].[x−a(c−a)xc(c−a)]=[x−ab+b2xa2−ab].[x−bc+c2xb2−bc].[x−ac+a2xc2−ac]=[x(a2−ab)−(−ab+b2)].[x(b2−bc)−(−bc+c2)].[x(c2−ac)−(−ac+a2)]=[xa2−ab+ab−b2].[xb2−bc+bc−c2].[xc2−ac+ac−a2]=[xa2−b2].[xb2−c2].[xc2−a2]=x(a2−b2)+(b2−c2)+(c2−a2)=xa2−b2+b2−c2+c2−a2=x0=1=RHS
∴ LHS = RHS
[x−bxa]a−b.[x−cxb]b−c.[x−axc]c−a=1