(p-4)(p-1)+3p
=p²-3p-4+3p
=p²-4
=(p+2)(p-2)请问第二部怎么出来的我有点看不懂不好意思，算错了 (p-4)(p-1)+3p=p²-5p+4+3p=p²-2p+4=p²-2p+1+3=(p-1)²-(3i)²=(p-1+3i)(p-1-3i)