2x4 - 6x3 + x2 + 6x - 3 = 0
⇔\(2x^4\)+\(2x^3\)-\(8x^3\)-\(8x^2\)+\(9x^2\) +9x -3x-3
⇔\(2x^3\)(x+1)-\(8x^2\)(x+1)+9x(x+1)-3(x+1)
⇔(\(2x^3\)-\(8x^2\)+9x-3)(x+1)
⇔(\(2x^3\)-\(2x^2\) -\(6x^2\)+6x+3x-3)(x+1)
⇔[\(2x^2\)(x-1)-6x(x-1)+3(x-1)](x+1)
⇔(\(2x^2\)-6x+3)(x-1)(x+1)
⇔(\(2x^2\)-6x+3)(x\(^2\)-1)