急!!中二math題目一條.15分
2009-08-15 10:13 pm
(x+a)(x-b)=x*x+x-c a.b.c是正整數.寫出2組a.b.c可能的值.....................諗左好耐......thx附加算式.
回答 (2)
2009-08-15 10:21 pm
✔ 最佳答案
(x + a)(x – b) = x*x + x – c(x + a)(x – b)
= x(x – b) + a (x – b)
= x*x – b*x + a*x – ab
= x*x + (a – b)x – ab
所以 a – b = 1; c = ab
若 b = 1, a = 2, c = 2
若 b = 2, a = 3 , c = 6
2009-08-15 10:21 pm
(x+a)(x-b)=x^2+x-c
x^2+(a-b)x-ab=x^2+x-c
(a-b-1)x=ab-c
a=2, b=1, c=2
a=3, b=2, c=6
x^2+(a-b)x-ab=x^2+x-c
(a-b-1)x=ab-c
a=2, b=1, c=2
a=3, b=2, c=6
收錄日期: 2021-04-23 23:18:05
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20090815000051KK00919