Results 1 to 11 of 11
Like Tree4Thanks
  • 2 Post By SlipEternal
  • 1 Post By DenisB
  • 1 Post By HallsofIvy

Thread: Algebra. Trying to learn and need help.

  1. #1
    Newbie
    Joined
    Apr 2018
    From
    Norway
    Posts
    9

    Algebra. Trying to learn and need help.

    Tom is 12 years older then sonny. In five years will Tom be twice his age then what Sonny was 4 years ago.

    How old are they?

    Thanksnfor the help if ther is any 😅😘
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    Joined
    Nov 2010
    Posts
    3,570
    Thanks
    1437

    Re: Algebra. Trying to learn and need help.

    Let's use letters. For Tom, we will use T. For Sonny, we will use S. The word is means equals. Older than means plus.
    $\displaystyle \begin{matrix}\text{Tom} & \text{is} & 12\text{ years} & \text{older than} & \text{Sonny} \\ T & = & 12 & + & S\end{matrix}$

    $\displaystyle \begin{matrix}\text{In five years will} & \text{Tom} & \text{be} & \text{twice} & \text{the age than what} & \text{Sonny was 4 years ago} \\ \text{(5 +} & T\text{)} & = & 2\times & ( & S-4\text{)}\end{matrix}$

    This gives two equations:
    $\displaystyle T=12+S$
    $\displaystyle (5+T) = 2(S-4)$

    Do you know how to solve a system of two equations?
    Thanks from topsquark and Greb
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    Apr 2018
    From
    Norway
    Posts
    9

    Re: Algebra. Trying to learn and need help.

    No, this is new to me.
    Follow Math Help Forum on Facebook and Google+

  4. #4
    MHF Contributor
    Joined
    Feb 2015
    From
    Ottawa Ontario
    Posts
    1,907
    Thanks
    352

    Re: Algebra. Trying to learn and need help.

    Is this a problem given to you by your math teacher?
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Newbie
    Joined
    Apr 2018
    From
    Norway
    Posts
    9

    Re: Algebra. Trying to learn and need help.

    This is a task from a math book for "High School". Im studing on my own until i start school agine. Soo no, a teacher did not give me this math problem
    Follow Math Help Forum on Facebook and Google+

  6. #6
    Newbie
    Joined
    Apr 2018
    From
    Norway
    Posts
    9

    Re: Algebra. Trying to learn and need help.

    Quote Originally Posted by SlipEternal View Post
    Let's use letters. For Tom, we will use T. For Sonny, we will use S. The word is means equals. Older than means plus.
    $\displaystyle \begin{matrix}\text{Tom} & \text{is} & 12\text{ years} & \text{older than} & \text{Sonny} \\ T & = & 12 & + & S\end{matrix}$

    $\displaystyle \begin{matrix}\text{In five years will} & \text{Tom} & \text{be} & \text{twice} & \text{the age than what} & \text{Sonny was 4 years ago} \\ \text{(5 +} & T\text{)} & = & 2\times & ( & S-4\text{)}\end{matrix}$

    This gives two equations:
    $\displaystyle T=12+S$
    $\displaystyle (5+T) = 2(S-4)$

    Do you know how to solve a system of two equations?
    No, this is new to me. coud you help me sovle it?
    Follow Math Help Forum on Facebook and Google+

  7. #7
    MHF Contributor
    Joined
    Feb 2015
    From
    Ottawa Ontario
    Posts
    1,907
    Thanks
    352

    Re: Algebra. Trying to learn and need help.

    Thanks from Greb
    Follow Math Help Forum on Facebook and Google+

  8. #8
    MHF Contributor

    Joined
    Apr 2005
    Posts
    19,864
    Thanks
    3074

    Re: Algebra. Trying to learn and need help.

    Quote Originally Posted by SlipEternal View Post
    Let's use letters. For Tom, we will use T. For Sonny, we will use S.
    When I was a teacher I discouraged language like that. You are really using "T" to represent Tom's age, not to represent "Tom". The same for "S". As we see at the end, "T" and "S" are numbers, not people!

    The word is means equals. Older than means plus.
    $\displaystyle \begin{matrix}\text{Tom} & \text{is} & 12\text{ years} & \text{older than} & \text{Sonny} \\ T & = & 12 & + & S\end{matrix}$

    $\displaystyle \begin{matrix}\text{In five years will} & \text{Tom} & \text{be} & \text{twice} & \text{the age than what} & \text{Sonny was 4 years ago} \\ \text{(5 +} & T\text{)} & = & 2\times & ( & S-4\text{)}\end{matrix}$

    This gives two equations:
    $\displaystyle T=12+S$
    $\displaystyle (5+T) = 2(S-4)$

    Do you know how to solve a system of two equations?
    Thanks from Greb
    Follow Math Help Forum on Facebook and Google+

  9. #9
    Newbie
    Joined
    May 2017
    From
    Canada
    Posts
    3
    Thanks
    1

    Re: Algebra. Trying to learn and need help.

    T = S + 12
    5+T = 2*(S - 4) => sub in T
    5+(S+12) = 2*(S - 4)

    5 + S + 12 = 4S - 8 => solve for S
    17 + 8 = 3S

    S = 25 / 3
    Follow Math Help Forum on Facebook and Google+

  10. #10
    MHF Contributor
    Joined
    Feb 2015
    From
    Ottawa Ontario
    Posts
    1,907
    Thanks
    352

    Re: Algebra. Trying to learn and need help.

    That's wrong Sky; try again: S = 25
    Follow Math Help Forum on Facebook and Google+

  11. #11
    MHF Contributor

    Joined
    Apr 2005
    Posts
    19,864
    Thanks
    3074

    Re: Algebra. Trying to learn and need help.

    Quote Originally Posted by jssky View Post
    T = S + 12
    5+T = 2*(S - 4) => sub in T
    5+(S+12) = 2*(S - 4)

    5 + S + 12 = 4S - 8 => solve for S
    2*(S- 4)= 2S- 8, not 4S- 8.

    17 + 8 = 3S

    S = 25 / 3
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 9
    Last Post: Jul 4th 2016, 06:39 AM
  2. Which Text book is best to learn the Algebra?
    Posted in the Algebra Forum
    Replies: 1
    Last Post: Aug 24th 2014, 08:39 AM
  3. Replies: 2
    Last Post: Mar 31st 2013, 04:08 PM
  4. Replies: 2
    Last Post: Mar 23rd 2013, 01:14 AM
  5. Replies: 8
    Last Post: Mar 16th 2010, 03:12 PM

/mathhelpforum @mathhelpforum