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    Hi all, I need help with this question. Been trying for ages with no luck.

    Using Pythagoras' Theorem, A = 4(x + 2), B = (x + 3), C = 25. Find X.

    help pls
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    (Original post by OwlnMcgee)
    Hi all, I need help with this question. Been trying for ages with no luck.

    Using Pythagoras' Theorem, A = 4(x + 2), B = (x + 3), C = 25. Find X.

    help pls
    You know a^2 + b^2 = c^2. You also know how to solve a quadratic.
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    (Original post by Zacken)
    You know a^2 + b^2 = c^2. You also know how to solve a quadratic.
    Yep. But I can't seem to actually solve the question.
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    (Original post by OwlnMcgee)
    Yep. But I can't seem to actually solve the question.
    What stage have you reached? You know that (4(x+2))^2 + (x+3)^2 = 25^2
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    (Original post by Zacken)
    What stage have you reached? You know that (4(x+2))^2 + (x+3)^2 = 25^2
    I don't know if this is right, but:

    4(x^2 + 2x + 4) + (x^2 + 3x + 3x + 9) = 25^2

    Another version that I ended up with was 5x^2 + 22x = 600.

    I've got really confused and ended up with many different outcomes, none actually being "final".
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    (Original post by OwlnMcgee)
    I don't know if this is right, but:

    4(x^2 + 2x + 4) + (x^2 + 3x + 3x + 9) = 25^2

    Another version that I ended up with was 5x^2 + 22x = 600.

    I've got really confused and ended up with many different outcomes, none actually being "final".
    (4(x+2))^2 = 4(x+2) \cdot 4(x+2) = 16(x^2 + 4x + 4)

    The second bracket is correct. So now simplify and solve.
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    (Original post by Zacken)
    (4(x+2))^2 = 4(x+2) \cdot 4(x+2) = 16(x^2 + 4x + 4)

    The second bracket is correct. So now simplify and solve.

    Okay, thanks. I got to 17x^2 + 70x = 552. What do I do now?
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    (Original post by OwlnMcgee)
    Okay, thanks. I got to 17x^2 + 70x = 552. What do I do now?
    Assuming that's correct, it's the same thing as 17x^2 + 70x - 552 = 0 which is a quadratic. Now... quadratic formula.
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    (Original post by Zacken)
    Assuming that's correct, it's the same thing as 17x^2 + 70x - 552 = 0 which is a quadratic. Now... quadratic formula.

    Yeah, I got to that. Can you please help me with the quadratic equation? I'm not too great at complex ones.
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    (Original post by OwlnMcgee)
    Yeah, I got to that. Can you please help me with the quadratic equation? I'm not too great at complex ones.
    Have you heard of the quadratic formula? Can you apply it in this scenario with
    a = 17, b=70, c = -552?
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    (Original post by Zacken)
    Have you heard of the quadratic formula? Can you apply it in this scenario with
    a = 17, b=70, c = -552?
    Yeah, I'm just looking at it now, haha. I'll give it a shot. (only learned quadratic equations like, three days ago so I'm not experienced with them yet)
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    (Original post by OwlnMcgee)
    Yeah, I'm just looking at it now, haha. I'll give it a shot. (only learned quadratic equations like, three days ago so I'm not experienced with them yet)
    Not a problem, don't worry. What do you get? The quadratic formula says that if you had a quadratic equation ax^2 + bx + c = 0, then your solutions are

    \displaystyle x = \frac{b \pm \sqrt{b^2 - 4ac}}{2a}
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    Uhhh, I've tried multiple different ways of using those numbers in the quadratic formula, but still don't get the right answer.

    Worst thing is, I get TWO wrong answers instead of one!
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    Zacken, you're a good kid. Stop letting the powers of community assistant get inside your head. I don't know the full story of the traumatic events that took place at your school leading you to drop out. However, physicsmaths has told me a bit about the bullies and I couldn't imagine how hard it must've been for you. Also, please don't take some of my immature posts too seriously, it's all banter.

    Take care bud!
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    (Original post by OwlnMcgee)
    Uhhh, I've tried multiple different ways of using those numbers in the quadratic formula, but still don't get the right answer.

    Worst thing is, I get TWO wrong answers instead of one!
    Do you mind posting your working so I can see where you went wrong?
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    (Original post by Zacken)
    Do you mind posting your working so I can see where you went wrong?
    Oh. I just tried it again and got it right.

    What was happening was first of all I got the operators wrong, and then it turns out I had to clear my calculator every time.

    Thank you all though!

    note: the answer was 4 cm
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    (Original post by OwlnMcgee)
    Oh. I just tried it again and got it right.

    What was happening was first of all I got the operators wrong, and then it turns out I had to clear my calculator every time.

    Thank you all though!

    note: the answer was 4 cm
    Great! Glad you got it.
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    (Original post by OwlnMcgee)
    Oh. I just tried it again and got it right.

    What was happening was first of all I got the operators wrong, and then it turns out I had to clear my calculator every time.

    Thank you all though!

    note: the answer was 4 cm
    Correct! Do you understand what wast done and why we arrived at the answer?
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    Yeah, I think so. Thanks again!
 
 
 
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