Question 696803
{{{(a-x)(b-c)-2(a-b)(b-c)=(c-x)(a-b)}}}
{{{ab-ac-bx+cx-2(ab-ac-b^2+bc)=ac-bc-ax+bx}}}
{{{ab-ac-bx+cx-2ab+2ac+2b^2-2bc=ac-bc-ax+bx}}}
{{{-bx+cx-ab+ac+2b^2-2bc=ac-bc-ax+bx}}}
{{{cx-ab+ac+2b^2-2bc=ac-bc-ax+2bx}}}
{{{-ab+ac+2b^2-2bc=ac-bc-ax+2bx-cx}}}
{{{-ab+2b^2-2bc=-bc-ax+2bx-cx}}}
{{{-ab+2b^2-bc=-ax+2bx-cx}}}
{{{b(-a+2b-c)=x(-a+2b-c)}}}
{{{b=x}}}