#Trying to figure out this equation

33 messages · Page 1 of 1 (latest)

gilded wren
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In this question when explaining the person goes from 1 - 2 and i am not sure how

  1. x^2 + 5x + 25/4 = 41/4
  2. (x + 5/2)^2 = 41/4
    Could someone explain how this is possible because when I complete the square of 1 I get (x+5/2)^2 - 5 + 25/4 = 41/4 which does not equal 2...
proven knoll
gilded wren
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not sure what you mean by that

native leaf
proven knoll
gilded wren
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so you just gotta realise that 41/4 can be factorised into (5/2)^2

proven knoll
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not 41/4

gilded wren
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25/4

proven knoll
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yes

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24/5 is (5/2)^2

gilded wren
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yes

proven knoll
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btw dismiss what I said about piecewise it is totally a different thing about graphs I mixed up with something

proven knoll
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bit more diagramic

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I said what can make "x^2"? It is "x*x"
then on to the constant number, what makes "25/4"? It is (5/2)^2

Great now the last thing you check is that do these 4 stuff we found give the middle part on the equation that has only "x" (like 5x you see)

You have to cross multiply it to find:

gilded wren
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I think i understand

proven knoll
# gilded wren I think i understand

sometimes it is not all roses and equation may contain negative component. Then you have to give different number like -(5/2)*-(5/2) again gives 25/4 but you can't find 5x after that. You would find -5x

gilded wren
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i am using this as a part of completing the square, would it still work on something like 3x^2 + 2x - 2

proven knoll
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yea

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It doesn't work on all equations

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tho

gilded wren
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how would the 3x^2 change this part?

proven knoll
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3x * x

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or

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-3x * -x

gilded wren
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oh okay

proven knoll
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and yeah

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you cannot find it on it

gilded wren
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right

proven knoll
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but because "b^2 - ac" shows that the Discriminant is higher that "0"

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it has two different values of x that complete equation to 0