Results 1 to 7 of 7

Math Help - Finish this equation

  1. #1
    Newbie
    Joined
    Jun 2012
    From
    california
    Posts
    3

    Finish this equation






    Not sure where to go from here
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    Joined
    Oct 2009
    Posts
    5,536
    Thanks
    778

    Re: Finish this equation

    y3 = 125 is equivalent to y = 5.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    Jun 2012
    From
    california
    Posts
    3

    Re: Finish this equation

    Sorry? What y? I need to find the value of x. The answer is supposedly 8.
    Follow Math Help Forum on Facebook and Google+

  4. #4
    MHF Contributor

    Joined
    Aug 2006
    Posts
    18,657
    Thanks
    1607
    Awards
    1

    Re: Finish this equation

    Quote Originally Posted by helvenmarn View Post
    Sorry? What y? I need to find the value of x. The answer is supposedly 8.
    (8-3)^3=125
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Newbie
    Joined
    Jun 2012
    From
    Ukraine
    Posts
    19
    Thanks
    9

    Re: Finish this equation

    (x-3)^3=125
    Since 125=5^3 then (x-3)^3=5^3.
    From this we have that x-3=5 or x=8
    Follow Math Help Forum on Facebook and Google+

  6. #6
    Newbie
    Joined
    Jun 2012
    From
    california
    Posts
    3

    Re: Finish this equation

    Ah thanks
    Follow Math Help Forum on Facebook and Google+

  7. #7
    Super Member
    Joined
    Jun 2012
    From
    AZ
    Posts
    616
    Thanks
    97

    Re: Finish this equation

    No need to expand.

    From (x-3)^3 = 125, we get x-3 = 5 \Rightarrow x = 8. There are also two roots in the complex plane, x = 3 + 5e^{\frac{2\pi i}{3}} and x = 3 + 5e^{\frac{4\pi i}{3}}
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. please finish trigonometric equation.
    Posted in the Trigonometry Forum
    Replies: 1
    Last Post: May 11th 2010, 10:03 AM
  2. Please help me finish this equation.
    Posted in the Algebra Forum
    Replies: 6
    Last Post: August 14th 2009, 02:19 PM
  3. how to finish this proof
    Posted in the Calculus Forum
    Replies: 3
    Last Post: December 2nd 2008, 11:40 AM
  4. Please need to finish homework
    Posted in the Calculus Forum
    Replies: 3
    Last Post: May 3rd 2008, 06:04 PM
  5. Can anyone help me finish this
    Posted in the Calculus Forum
    Replies: 4
    Last Post: March 12th 2008, 03:47 PM

Search Tags


/mathhelpforum @mathhelpforum