Để A < 1 thì :
\(\Leftrightarrow\)\(\frac{\left(x-1\right)^2}{x^2-4x+3}< 1\)
\(\Leftrightarrow\)(x-1)2 < x2-4x+3
\(\Leftrightarrow\)x2-2x+1< x2-4x+3
\(\Leftrightarrow\)x2-x2-2x+4x<3-1
\(\Leftrightarrow\)2x <2
\(\Leftrightarrow\)x <1
Vậy bpt có nghiệm x<1