1.The sum of a number and its square is 20.Find all such numbers.
呢個問題系解咩啊，可唔可以教下我做，thx...........
2.The sum of a number and its reciprocal is 13/6.Find all such numbers.
-reciprocal系點解呢?
請解答以上兩條問題，thx..........
f4 math.....(10分)
2008-03-24 3:08 am
回答 (2)
2008-03-24 4:13 am
✔ 最佳答案
1. let x be the number,x + x^2=20
x^2 + x-20=0
(x+5)(x-4)=0
x=-5 or x=4 (both answers are correct)
2. let x be the number,
x + 1/x = 13/6
x^2 +1=13x/6
6x^2-13x+6=0
(2x-3)(3x-2)=0
x=3/2 or x=2/3
2008-03-24 3:20 am
第一條:
(一個數)+(佢自己既2次)=20
4 + 4*4 =20
第二條:
(一個數)+(一個數既倒數) 倒數指(分子分母倒轉)
2/3 + 3/2 e.g 10既倒數係1/10
= 4/6 + 9/6 5/43既倒數係43/5
=13/6
唔明可以MSN問我~
[email protected]
(一個數)+(佢自己既2次)=20
4 + 4*4 =20
第二條:
(一個數)+(一個數既倒數) 倒數指(分子分母倒轉)
2/3 + 3/2 e.g 10既倒數係1/10
= 4/6 + 9/6 5/43既倒數係43/5
=13/6
唔明可以MSN問我~
[email protected]
收錄日期: 2021-04-29 20:26:18
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https://hk.answers.yahoo.com/question/index?qid=20080323000051KK02424