a(x-p)(x-3)=a(x²-3x-px+3p)=a[x²-(3+p)x+3p]=ax²-(3+p)ax+3pa=ax^2+2x+3所以：{-(3+p)a=2 3pa=3解得：{a=-1 p=-1
由题意得，（-3-p）a=2，3ap=3得 a= -1，p= -1
