Bài 1:
a) Ta có: x(x-3)-(x-2)x=8
\(\Leftrightarrow x^2-3x-x^2+2x-8=0\)
\(\Leftrightarrow-x-8=0\)
\(\Leftrightarrow-x=8\)
hay x=-8
Vậy: x=-8
b) Ta có: (x-1)(x-5)-x(x-4)=12
\(\Leftrightarrow x^2-6x+5-x^2+4x-12=0\)
\(\Leftrightarrow-2x-7=0\)
\(\Leftrightarrow-2x=7\)
hay \(x=\frac{-7}{2}\)
Vậy: \(x=\frac{-7}{2}\)