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Post by I'm tired of changing my name. on May 22, 2009 9:16:56 GMT -5
I just need a little help on grouping and those dammed quadratic trinomials! Need help!
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Post by TomBeasley on May 24, 2009 5:14:38 GMT -5
What level are you at?
Perhaps explain further what you're struggling with.
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Post by applePAI! on May 24, 2009 18:49:59 GMT -5
Quadratic Trinomials! Love those things! Good timing, we just finished up with that =D But yeah, need to know where you're at with it in order to help.
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adam
Year 1
Super Pro, I am Beast!
Posts: 6
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Post by adam on May 25, 2009 7:42:38 GMT -5
I am smart at math, I am in the better math, what level are you at?
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Post by I'm tired of changing my name. on May 27, 2009 5:22:04 GMT -5
I'm in 1st Year (Irish) But basically I've just started them.
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Post by TomBeasley on May 27, 2009 12:12:02 GMT -5
I have never heard the phrase "Quadratic Trinomials" before.
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Post by iiPod on May 27, 2009 12:29:07 GMT -5
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Post by TomBeasley on May 27, 2009 12:31:22 GMT -5
Oh. I can do them. I've just never heard that name for them.
I'll do you a little tutorial for how to do them in a sec.
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Post by TomBeasley on May 27, 2009 12:54:03 GMT -5
Basically, a quadratic trinomial comes in the form of ax 2 + bx + c = 0 and usually have two different possible solutions for x. They can be solved in two ways and I will explain both of these now. Factorisingx 2 - 7x + 6 = 0 In order to solve x, you must first take c, which is +6. Then see what two numbers can be multiplied together to make +6. These could be either 1&6 or 2&3. Then pick the combination that can be added together to make b, which is -7. Once you have these terms, you can place them into a double bracket that, when multiplied out, will give the above equation. (x - 1)(x - 6) = 0 I will now multiply these out to see whether it gives the correct equation. x times x = x 2x times -6 = -6x -1 times x = -1x -1 times -6 = +6 This gives the equation: x 2 - 7x + 6 = 0 Therefore, we have factorised correctly. Now we just need to finish solving the equation. In order for the double bracketed equation to equal 0, one of the brackets must be 0. Therefore, either: x - 1 = 0 so x = 1 or x - 6 = 0 so x = 6 So, the two possible solutions for x are 1 and 6.FormulaThe other way of doing it is to use the quadratic formula, which is:
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Post by applePAI! on May 27, 2009 14:30:35 GMT -5
I take it back o__o I don't know those. But now I do. YAY! I'm smarter now DX Thanks!
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Post by TomBeasley on May 27, 2009 15:25:53 GMT -5
No problem. I do try to help, as you can see by my epic long article in the English board that no-one has commented on.
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Post by iiPod on May 28, 2009 7:21:19 GMT -5
Oh, I have done those before... But under a different name
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Post by TomBeasley on May 28, 2009 8:41:03 GMT -5
Yeah. They were just called quadratics when I did them. The "trinomials" bit was what threw me off course.
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Post by Jimmythenumbers on May 29, 2009 15:08:11 GMT -5
I'm going to be picky here, there are not always two solutions to a quadratic equation. The easiest and laziest example for this is to set a, b and c to 0.
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Post by TomBeasley on May 30, 2009 15:37:46 GMT -5
Fair point. In most examples, there are two solutions though.
I've edited the advice to say that they usually have two.
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