Results 1 to 4 of 4

Math Help - I forgot how to do this...

  1. #1
    Newbie
    Joined
    Aug 2009
    Posts
    4

    I forgot how to do this...

    Problem: "The graph of a quadratic function has a vertex at (-3,7) and a Y-intercept of 18. Name any other point on the parabola."
    Y-7= a(x+3)^2 is the only thing that comes to mind, and It's not really helping me solve this question...

    Identical problem: "Find a particuar equation of the quadratic function that passes through a vertex of (5,-1) and the point (8,-28)."

    Any help would be much appreciated.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    skeeter's Avatar
    Joined
    Jun 2008
    From
    North Texas
    Posts
    12,108
    Thanks
    970
    Quote Originally Posted by MadCow8890 View Post
    Problem: "The graph of a quadratic function has a vertex at (-3,7) and a Y-intercept of 18. Name any other point on the parabola."
    Y-7= a(x+3)^2 is the only thing that comes to mind, and It's not really helping me solve this question...

    Identical problem: "Find a particuar equation of the quadratic function that passes through a vertex of (5,-1) and the point (8,-28)."

    Any help would be much appreciated.
    y = a(x+3)^2 + 7

    (0,18) is the y-intercept ...

    18 = a(0+3)^2 + 7

    solve for "a"
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    Aug 2009
    Posts
    4
    I'm just checking with with you (or anyone really), if that's okay. (Sorry, it's the beginning of the year and I forgot nearly everything over the summer.) Does a = -5?

    Work:
    18= a(9) + 7
    2 = a + 7
    -5 = a
    Follow Math Help Forum on Facebook and Google+

  4. #4
    MHF Contributor
    skeeter's Avatar
    Joined
    Jun 2008
    From
    North Texas
    Posts
    12,108
    Thanks
    970
    Quote Originally Posted by MadCow8890 View Post
    I'm just checking with with you (or anyone really), if that's okay. (Sorry, it's the beginning of the year and I forgot nearly everything over the summer.) Does a = -5?

    Work:
    18= a(9) + 7
    2 = a + 7
    -5 = a
    you forgot how to solve these, too ? ...

    18 = 9a + 7

    subtract 7 first ...

    11 = 9a

    divide by 9 ...

    11/9 = a
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 0
    Last Post: March 10th 2010, 07:24 AM
  2. I forgot how to do this...help.
    Posted in the Calculus Forum
    Replies: 2
    Last Post: December 16th 2009, 12:29 PM
  3. Forgot
    Posted in the Algebra Forum
    Replies: 5
    Last Post: August 20th 2009, 11:39 PM
  4. some how forgot
    Posted in the Calculus Forum
    Replies: 2
    Last Post: February 27th 2009, 04:37 AM
  5. Need help! Forgot how to do this..
    Posted in the Calculus Forum
    Replies: 1
    Last Post: January 1st 2009, 02:18 PM

Search Tags


/mathhelpforum @mathhelpforum