已知a平方+b平方=20.ab=5.求(a-b)平方=?
完整過程~
thank~~~~~~~~~~
平方計算題~
2011-12-28 3:16 am
回答 (2)
2011-12-28 3:22 am
✔ 最佳答案
(a - b)²= a² - 2ab + b²
= (a² + b²) - 2(ab)
= (20) - 2(5)
= 10
2011-12-28 3:42 am
a^2+b^2=20
ab=5
(a-b)^2
=a^2-2ab+b^2
=20-2(5)
=10
ab=5
(a-b)^2
=a^2-2ab+b^2
=20-2(5)
=10
收錄日期: 2021-04-21 22:23:12
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20111227000051KK00702