\(a.x^2-3x+2=\left(x^2-x\right)+\left(-2x+2\right)\)
\(=x\left(x-1\right)-2\left(x-1\right)=\left(x-1\right)\left(x-2\right).\)
\(b.x^2-6x+8=\left(x^2-2x\right)+\left(-4x+8\right)\)
\(=x\left(x-2\right)-4\left(x-2\right)=\left(x-2\right)\left(x-4\right).\)
\(c.x^2-8x+7=\left(x^2-x\right)+\left(-7x+7\right)\)
\(=x\left(x-1\right)-7\left(x-1\right)=\left(x-1\right)\left(x-7\right).\)
\(d.3x^2-8x+5=\left(3x^2-3x\right)+\left(-5x+5\right)\)
\(=3x\left(x-1\right)-3\left(x-1\right)=\left(x-1\right)\left(3x-5\right).\)
\(e.4x^2-11x+7=\left(4x^2-4x\right)+\left(-7x+7\right)\)
\(=4x\left(x-1\right)-7\left(x-1\right)=\left(x-1\right)\left(4x-7\right).\)
\(f.6x^2-13x-5=\left(6x^2+2x\right)+\left(-15x-5\right)\)
\(=2x\left(3x+1\right)-5\left(3x+1\right)=\left(3x+1\right)\left(2x-5\right).\)
