a ) \(\left(x-3\right).\left(x+2\right)+\left(x-1\right).\left(x+1\right)-\left(2x-1\right)x\)
\(=x.\left(x+2\right)-3.\left(x+2\right)+x.\left(x+1\right)-1.\left(x+1\right)-\left(2x-1\right)x\)
\(=x^2+2x-3x-6+x^2+x-x-1-2x^2+x\)
\(=-6\)
\(\RightarrowĐPCM\)