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Thread: brackets within brackets

  1. #1
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    brackets within brackets

    hi how would I work out the following?
    (3(2^2 -2)^2 -10)^2

    which brackets do I calculate first please?
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  2. #2
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    Quote Originally Posted by wolfhound View Post
    hi how would I work out the following?
    (3(2^2 -2)^2 -10)^2

    which brackets do I calculate first please?
    Start with the innermost and move outwards:

    1. $\displaystyle 2^2-2 = {\color{red}2}$
    2. $\displaystyle {\color{red}2}^2 = {\color{blue}4}$
    3. $\displaystyle 3 \times {\color{blue}4} = {\color{green}12}$
    4. $\displaystyle {\color{green}12} - 10 = 2$
    5. $\displaystyle 2^2 = 4$
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  4. #4
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    You can also use google calculator to check your answer. Paste the problem into google and hit search

    http://www.google.com/#hl=en&source=hp&q=%283%282^2+-2%29^2+-10%29^2&aq=f&aqi=&oq=&fp=e705e53e3f505592
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  5. #5
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    value of x

    find value of x if x-2 =5x + 14
    more helps please

    I havent learned how to do these yet I just want to find out how and then I will catch on
    Thanks
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  6. #6
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    Quote Originally Posted by wolfhound View Post
    find value of x if x-2 =5x + 14
    more helps please

    I havent learned how to do these yet I just want to find out how and then I will catch on
    Thanks

    HI

    $\displaystyle x-2=5x+14$

    $\displaystyle x-5x=14+2$

    $\displaystyle
    -4x=16
    $

    $\displaystyle
    x=-4
    $
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  7. #7
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    Quote Originally Posted by mathaddict View Post
    HI

    $\displaystyle x-2=5x+14$

    $\displaystyle x-5x=14+2$

    $\displaystyle
    -4x=16
    $

    $\displaystyle
    x=-4
    $
    cool thanks
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  8. #8
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    another find x

    How about this one
    find value of x if
    2x-1/x+2 = 3

    and
    is 5 a solution of x^2 + 3x-9=(x-4)(x+21)??
    If so please explain how I do it
    Thanks!!!!!
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  9. #9
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    actually is x =7 the first one...
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  10. #10
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    Quote Originally Posted by wolfhound View Post
    How about this one
    find value of x if
    2x-1/x+2 = 3

    and
    is 5 a solution of x^2 + 3x-9=(x-4)(x+21)??
    If so please explain how I do it
    Thanks!!!!!
    HI again .

    If you need any more help , its better to start a new thread . Well , i am going to answer this . If you have any more q's , start a new onw

    $\displaystyle \frac{2x-1}{x+2}=3$

    $\displaystyle 2x-1=3(x+2)$

    $\displaystyle 2x-1=3x+6$

    $\displaystyle x=-7$


    $\displaystyle
    x^2+3x-9=(x-4)(x+21)
    $

    $\displaystyle x^2+3x-9=x^2+17x-84$

    $\displaystyle 3x-9=17x-84$

    $\displaystyle 14x=75$

    $\displaystyle x=75/14$

    So 5 is not a solution .
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  11. #11
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    Quote Originally Posted by mathaddict View Post
    HI again .

    If you need any more help , its better to start a new thread . Well , i am going to answer this . If you have any more q's , start a new onw

    $\displaystyle \frac{2x-1}{x+2}=3$

    $\displaystyle 2x-1=3(x+2)$

    $\displaystyle 2x-1=3x+6$

    $\displaystyle x=-7$


    $\displaystyle
    x^2+3x-9=(x-4)(x+21)
    $

    $\displaystyle x^2+3x-9=x^2+17x-84$

    $\displaystyle 3x-9=17x-84$

    $\displaystyle 14x=75$

    $\displaystyle x=75/14$

    So 5 is not a solution .
    Thanks so much for your help I will start a new thread when I have more questions...
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  12. #12
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    e^(i*pi)'s Avatar
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    You seem to have the wrong sign for both of them

    $\displaystyle \frac{2(7)-1}{7+2} = \frac{13}{9} \neq 3$

    by inspection $\displaystyle x = -7$

    -----------------

    For the 2nd one $\displaystyle 31 \neq 26$ so 5 is not a solution

    $\displaystyle x^2+3x-9 = x^2+17x-84$

    $\displaystyle -14x = - 75$
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