18/01/24 00:23:14.59 9ooAixL8.net
>>168
xx-3x-1 =（x-a)(x-b）= xx -(a+b)x +ab,
a+b=3，ab=-1
c+d =（b+1)/a + (a+1)/b
=｛b(b+1）+ a(a+1)}/(ab)
=（a+b)(a+b+1)/(ab）-2
=（3･4)/(-1）-2
= -14,
cd =｛(b+1)/a}･{(a+1)/b｝
= 1 +（a+b+1)/(ab)
=（-1+3+1)/(-1)
= -3,
（x-c)(x-d）= xx -(c+d)x +cd
= xx+14x-3.