It is given that x#y=xy-x-y+1. a and b are positive integers and 10 =a#b. what is the
sum of all possible values of a.
maths plz help 急!!!
2013-05-22 8:12 pm
回答 (1)
2013-05-22 8:28 pm
✔ 最佳答案
x#y = xy – x – y + 1 = x(y – 1) – (y – 1) = (x – 1)(y – 1) ∴ (a – 1)(b – 1) = 10a – 1 = 1, 2, 5 or 10 a = 2, 3, 6, 11 ∴ Sum of all possible values of a= 2 + 3 + 6 + 11 = 22
參考: My Maths World
收錄日期: 2021-04-13 19:28:45
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20130522000051KK00100