Results 1 to 2 of 2

Math Help - System of Equations?

  1. #1
    Newbie
    Joined
    Oct 2009
    Posts
    24

    System of Equations?

    Consider the following system of three equations in three unknowns.
    2x − y + z = −9
    x + y + 4z = −17
    3x + 4y − z = 2

    (a) Solve the first equation for z.

    z = -9-2x+y

    (b) Put the solution you got in part (a) for z into both the second and third equations. Solve each equation for y.

    2nd equation y = (19+7x)/5
    3rd equation y = (-7-5x)/3

    (c) Solve the system of two equations in two unknowns that you found in part (b).

    (x,y) =

    (d) Write the solution of the original system of three equations in three unknowns.

    (x,y,z) =


    I'm not quite sure how to get the points. Do I use the second or first equation, substitute y and z and solve for x? I don't even know how to begin to solve for z...
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Banned
    Joined
    May 2009
    Posts
    471
    Quote Originally Posted by MathBane View Post
    Consider the following system of three equations in three unknowns.
    2x − y + z = −9
    x + y + 4z = −17
    3x + 4y − z = 2

    (a) Solve the first equation for z.

    z = -9-2x+y

    (b) Put the solution you got in part (a) for z into both the second and third equations. Solve each equation for y.

    2nd equation y = (19+7x)/5
    3rd equation y = (-7-5x)/3

    (c) Solve the system of two equations in two unknowns that you found in part (b).

    (x,y) =

    (d) Write the solution of the original system of three equations in three unknowns.

    (x,y,z) =


    I'm not quite sure how to get the points. Do I use the second or first equation, substitute y and z and solve for x? I don't even know how to begin to solve for z...
    Set the 2nd and 3rd equation equal to eachother, this will get you x and y, then plug these points into z=-9-2x+y to get z
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. system of equations
    Posted in the Algebra Forum
    Replies: 6
    Last Post: September 27th 2011, 05:05 AM
  2. system of equations
    Posted in the Differential Equations Forum
    Replies: 0
    Last Post: May 4th 2010, 02:35 PM
  3. Replies: 2
    Last Post: April 20th 2010, 03:26 PM
  4. system of equations
    Posted in the Pre-Calculus Forum
    Replies: 4
    Last Post: January 26th 2010, 04:26 AM
  5. system of equations
    Posted in the Algebra Forum
    Replies: 3
    Last Post: July 13th 2008, 11:01 AM

Search Tags


/mathhelpforum @mathhelpforum