2lgx-lg(x-1)=2(1-lg5)
lgx^2-lg(x-1)=2(lg10-lg5)
lg[x^2/(x-1)]=2lg2
lg[x^2/(x-1)]=lg4
x^2/(x-1)=4
x^2-4x+4=0
(x-2)^2=0
x=2