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| Thread ID: 50794 | 2004-11-02 00:18:00 | OT homework help | veterannz (960) | Press F1 |
| Post ID | Timestamp | Content | User | ||
| 286896 | 2004-11-02 00:18:00 | My daughter brought home some pre exam homework and after 40 years being away from school , I am unable to help her with the following sum. Simplify the following X2 + 8 X +15 ------------------ X + 5 where I have written X2, I mean X squared. Apparently the answer is X + 3 but the only answer iI can get is X + 11. I hope there is someone out there who can show me how to get the correct answer |
veterannz (960) | ||
| 286897 | 2004-11-02 00:38:00 | 1st clue: What is 15 divided by 5? |
b1naryb0y (3) | ||
| 286898 | 2004-11-02 00:57:00 | I realise that I'm doing it wrongly but......... If I divide thru by X i get X + 8 + 15 ------------- 5 if i divide those numbers which are divisible top and bottom by 5 I get X + 8 + 3. So what am I doing wrong???? If I do as you suggest and just simplify the 15 and 5, what do you suggest I do with the *? |
veterannz (960) | ||
| 286899 | 2004-11-02 00:58:00 | but the only answer iI can get is X + 11 Although x + 3 is the answer, the learning thing is to clarify how you arrived at x + 11. |
TonyF (246) | ||
| 286900 | 2004-11-02 00:58:00 | oooops * should have read 8 | veterannz (960) | ||
| 286901 | 2004-11-02 01:03:00 | How old is your daughter? Let's just proof that (x+5) (x+3) is the correct answer (x+5) (x+3) = (x*x)+(x*3)+(5*x)+(5*3) =x^2+3x+5x+15 =x^2+8x+15 There you go. Simple. How can you get x+11? (x+5) (x+11) =x^2+16x+55 !!! I'm a little suprised that although it's being 40 years since you left school, that you don't know this. Please don't remind me of the failing literacy and numeracy standards ... :( Sorry, I don't know how you get the correct answer in step by step ways of doing things. I guess it would just be trial and error. But I can clearly see the answer just looking at it. Maybe it's just that I've done a million of these... The only way I could think of is when you see a x^2 followed by something x and a number is to (x +/- ?) (x+/-?).. then take the number and find the factors of it. See if using these two numbers, you can somehow add or subtract to get the middle number. I'm not sure if you can understand that, but it's probably the best I can do. |
~~~~~ s y ~~~~~ (2054) | ||
| 286902 | 2004-11-02 01:14:00 | My daughter is 13. I'm surprised that you are amazed at my lack of numeracy and literacy. I have not done algebra since 1955 and I was pleased that I still had a slight understanding of the problem. Whilst my literacy and numeracy are not up to your standards, at least my tolerance for those who dont have your supernatural talents must surely exceed yours. I only wanted a simple answer so I could help my daughter, not an example of the arrogance of the few !! I presume you are not a teacher as your solution is not aimed at lesser beings such as myself.. |
veterannz (960) | ||
| 286903 | 2004-11-02 01:16:00 | by the way the answer supplied by the NZQA is X + 3 not (x+5) (x+3) | veterannz (960) | ||
| 286904 | 2004-11-02 01:18:00 | Sorry, but I did not mean any offence. There was nothing in your post or mine that suggested you had literacy standards of any sort, I'm just generalising. And no, I'm not a teacher... Maybe I should stop helping people with Maths problems on this forum... I've taken all the effort to type out step by step, yet, you come and teach me about my lack of tolerance. |
~~~~~ s y ~~~~~ (2054) | ||
| 286905 | 2004-11-02 01:20:00 | yes ok, well, If (x+5) times (x+3) = x^2+8x+15 Then x^2+8x+15 divided by x+5 will be x+3 Just like 2*6=12 So 12/2=6 |
~~~~~ s y ~~~~~ (2054) | ||
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