\(a.x(x-3)-x^2=6\)
\(-3x=6\)
\(x=-2\)
\(b.x(x+2)-x-2=0\)
\(x(x+2)-(x+2)=0\)
\((x+2)(x-1)=0\)
\(\Leftrightarrow\left[ \begin{array}{l}x+2=0\\x-1=0\end{array} \right.\)
\(\Leftrightarrow\left[ \begin{array}{l}x=-2\\x=1\end{array} \right.\)
\(c.(x-3)(x^2+3x+9)-x^3+2x=-7\)
\(x^3-9-x^3+2x=-7\)
\(2x-20=0\)
\(x=10\)
\(2x(x^2-1)=2\)
\(d.x(x-3)-x+3=0\)
\(x(x-3)-(x-3)=0\)
\((x-3)(x-1)=0\)
\(\Leftrightarrow\left[ \begin{array}{l}x-3=0\\x-1=0\end{array} \right.\)
\(\Leftrightarrow\left[ \begin{array}{l}x=3\\x=1\end{array} \right.\)
