Results 1 to 3 of 3

Math Help - [SOLVED] Graphing systems of equations.

  1. #1
    Newbie haflore's Avatar
    Joined
    Feb 2008
    Posts
    18

    [SOLVED] Graphing systems of equations.

    I've got a few questions that I believe I solved correctly but wanted to check on. I have graphed them and they seem to check out....


    The questions, and my working for them, are as follows:

    1: 3x+y=5
    -2+3y=4
    -------------------------------------
    3x+y=5 ->

    3x+y-3x=5-3x ->

    y=5-3x therefore

    if: x=0 y=5

    x=1 y=2

    x=2 y=(-1)
    -------------------------------------
    -2x+3y=4 ->

    -2x+3y-(-2x)=4-(-2x) ->

    3y=4+2x ->

    y = 4/3 + (2/3)x therefore

    if: x = 0 y = 1 1/3

    x = 1 y = 2

    x = 2 y = 2 2/3

    ********************************
    answer is: x = 1 y = 2, the lines intersect.
    __________________________________________________ _____
    2: 2x = y + 1
    2x - y = 5
    ------------------------------------------
    2x = y + 1 ->

    y = 2x - 1 therefore

    if: x = 0 y = (-1)

    x = 1 y = 1

    x = 2 y = 3
    -----------------------------------------
    2x - y = 5 ->

    2x - y + 2x = 5 + 2x ->

    y = 5 + 2x therefore

    if: x = 0 y = 5

    x = 1 y = 7

    x = 2 y = 9
    ***************************
    answer is: none, the lines are parallel
    _______________________________________
    3: 3x + 2y = 8
    6x + 4y = 16
    ----------------------------------------
    3x + 2y = 8 ->

    3x + 2y - 3x = 8 - 3x ->

    2y = 8 - 3x ->
    y = 4 - (3/2)x therefore

    If: x=0 y=4

    x=1 y=2 1/2

    x=2 y=1
    -----------------------------------------
    6x+4y=16 ->

    6x+4y-6x=16-6x ->

    4y=16-6x ->

    y=4-(3/2)x therefore

    If: x=0 y=4

    x=1 y=2 1/2

    x=2 y=1
    *********************************
    answer: infinite, the lines coincide

    ________________________________________

    Thanks!
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Newbie
    Joined
    Feb 2008
    Posts
    3

    graphing systems of equations

    Your answers are correct, but I did them by solving simultaneous equations
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie haflore's Avatar
    Joined
    Feb 2008
    Posts
    18
    Thanks newbold!
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Graphing 2X2 systems
    Posted in the Differential Equations Forum
    Replies: 0
    Last Post: September 14th 2009, 06:54 PM
  2. Replies: 7
    Last Post: August 30th 2009, 10:03 AM
  3. Replies: 2
    Last Post: August 8th 2009, 03:02 PM
  4. Graphing systems of equations?
    Posted in the Pre-Calculus Forum
    Replies: 1
    Last Post: August 5th 2008, 09:34 AM
  5. [SOLVED] Systems of Equations - Work Related
    Posted in the Algebra Forum
    Replies: 1
    Last Post: October 3rd 2007, 08:23 AM

Search Tags


/mathhelpforum @mathhelpforum