(6x-1)(2x-1)(3x-1)(x-1)+x^2 =[(6x-1)(x-1)][(2x-1)(3x-1)]+x^2 =[(6x^2+1)-7x][(6x^2+1)-5x]+x^2 =(6x^2+1)^2-12x(6x^2+1)+35x^2+x^2=(6x^2+1)^2-12x(6x^2+1)+36x^2=(6x^2+1)^2-2*(6x)*(6x^2+1)+(6x)^2=(6x^2-6x+1)^2
