limx→5x2−9x+20x2−6x+5
=limx→5x2−4x−5x+20x2−x−5x+5
=limx→5x(x−4)−5(x−4)(x−1)−5(x−1)
=limx→5(x−5)(x−4)(x−5)(x−1)
=limx→5x−4x−1
=5−45−1
=14
px−qx2+2x+13x3+x2+2x+63x3+6x2+3x––––––––––––––––2−5x2−x+5−5x2−10x−5–––––––––––––––––9x+10
limx→∞(5x2+x+3x2+x+3)1x (2002)