Page 2 of 3 FirstFirst 123 LastLast
Results 16 to 30 of 33

Math Help - system of linear equations

  1. #16
    Junior Member
    Joined
    Aug 2006
    Posts
    38

    solving systems of two linear equations in two unknows algebraically

    Set up appropriate systems of two linear equations and slove the systems algebraically. all data are accurate to at least two significant digits.

    the weight Wf supported by the front wheels of a certain car and the weight Wr supported by the rear wheels together equal the weight of the car, 17700N. also , the ratio of Wr to Wf is 0.847. what are the weights supported by each set of wheels??

    can any kind hearted help me out with this word problems
    Follow Math Help Forum on Facebook and Google+

  2. #17
    dan
    dan is offline
    Member dan's Avatar
    Joined
    Jun 2006
    From
    nebraska usa
    Posts
    113
    do you know anything about matrices??? the cramer's rule is pretty simple if you know matrix algebra...
    dan
    Follow Math Help Forum on Facebook and Google+

  3. #18
    dan
    dan is offline
    Member dan's Avatar
    Joined
    Jun 2006
    From
    nebraska usa
    Posts
    113
    Quote Originally Posted by danielwu
    Set up appropriate systems of two linear equations and slove the systems algebraically. all data are accurate to at least two significant digits.

    the weight Wf supported by the front wheels of a certain car and the weight Wr supported by the rear wheels together equal the weight of the car, 17700N. also , the ratio of Wr to Wf is 0.847. what are the weights supported by each set of wheels??

    can any kind hearted help me out with this word problems
    here i think you have...someone correct me if i'm wrong...
     W_f + W_r =17700
     (0.847)W_r - W_f =0
    ~dan
    Follow Math Help Forum on Facebook and Google+

  4. #19
    Junior Member
    Joined
    Aug 2006
    Posts
    38
    Quote Originally Posted by dan
    do you know anything about matrices??? the cramer's rule is pretty simple if you know matrix algebra...
    dan
    nope i am sorry i dont know about matrix algebra
    Follow Math Help Forum on Facebook and Google+

  5. #20
    Junior Member
    Joined
    Aug 2006
    Posts
    38
    Quote Originally Posted by dan
    here i think you have...someone correct me if i'm wrong...
     W_f + W_r =17700
     (0.847)W_r - W_f =0
    ~dan
    <br />
I have the answer as W_r = 8120N, W_f = 9580N <br />
    As for this. how should i go about to solve??
     W_f + W_r =17700
     (0.847)W_r - W_f =0
    Follow Math Help Forum on Facebook and Google+

  6. #21
    Global Moderator

    Joined
    Nov 2005
    From
    New York City
    Posts
    10,616
    Thanks
    9
    Want to learn about them?
    (Post #7 and #16)
    Follow Math Help Forum on Facebook and Google+

  7. #22
    dan
    dan is offline
    Member dan's Avatar
    Joined
    Jun 2006
    From
    nebraska usa
    Posts
    113
    Quote Originally Posted by dan
    here i think you have...someone correct me if i'm wrong...
     W_f + W_r =17700
     (0.847)W_r - W_f =0
    ~dan
    then by adding you wold have  (1.847)W_r =17700
     W_r = \frac{17700}{1.847} =9583.12
    and  W_r(0.874)=W_f

    ~dan
    Follow Math Help Forum on Facebook and Google+

  8. #23
    Junior Member
    Joined
    Aug 2006
    Posts
    38

    0.847?

    Quote Originally Posted by dan
    then by adding you wold have  (1.847)W_r =17700
     W_r = \frac{17700}{1.847} =9583.12
    and  W_r(0.874)=W_f

    ~dan
    how and why 0.874 is change to 1.874??
    Follow Math Help Forum on Facebook and Google+

  9. #24
    Junior Member
    Joined
    Aug 2006
    Posts
    38

    ?

    Quote Originally Posted by ThePerfectHacker
    Want to learn about them?
    (Post #7 and #16)
    those are determinants method

    i mean the question i post was solving by algebraically.
    which than i am confused in doing so!
    i can use cramer's rule and i am quite okay with it, just that algebraically i am real bad at it.
    Follow Math Help Forum on Facebook and Google+

  10. #25
    Newbie
    Joined
    Dec 2005
    From
    Kolkata, India
    Posts
    19
    Quote Originally Posted by danielwu
    <br />
I have the answer as W_r = 8120N, W_f = 9580N <br />
    As for this. how should i go about to solve??
     W_f + W_r =17700
     (0.847)W_r - W_f =0
    You just have to see how can you reduce two equations having two variables to a single equation having one variable.

    So, add both the equations.
    W_f goes out and the resultant equation contains only one variable, i.e., W_r. The resulting equations is
    W_r+0.847W_r=17700+0
    1.847W_r=17700
    W_r=\frac{17700}{1.847}\approx9583.11
    Then substitute the value of W_r in one of the previous equations to find W_f
    Follow Math Help Forum on Facebook and Google+

  11. #26
    MHF Contributor Quick's Avatar
    Joined
    May 2006
    From
    New England
    Posts
    1,024
    Quote Originally Posted by danielwu
    how and why 0.874 is change to 1.874??
    You know that W_f=1770-W_r

    you also know that 0.847W_r=W_f

    subsitute: 0.847W_r=1770-W_r

    add: 0.847W_r+1W_r=1770

    add: 1.847W_r=1770
    Follow Math Help Forum on Facebook and Google+

  12. #27
    Junior Member
    Joined
    Aug 2006
    Posts
    38

    oh i got it!

    Quote Originally Posted by Quick
    You know that W_f=1770-W_r

    you also know that 0.847W_r=W_f

    subsitute: 0.847W_r=1770-W_r

    add: 0.847W_r+1W_r=1770

    add: 1.847W_r=1770
    thanks alot...!!
    Follow Math Help Forum on Facebook and Google+

  13. #28
    dan
    dan is offline
    Member dan's Avatar
    Joined
    Jun 2006
    From
    nebraska usa
    Posts
    113
    Quote Originally Posted by danielwu
    how and why 0.874 is change to 1.874??
    you have the system:
     (1)W_r + (1)W_f =17700
     (.874) W_r + (-1)W_f =0
    add the coefficients to get
     (1+.874)W_r + (1+-1)W_f = 0+17700
    or  (1.874)W_r=17700
    let me know if that made sence...

    dan
    Follow Math Help Forum on Facebook and Google+

  14. #29
    Junior Member
    Joined
    Aug 2006
    Posts
    38
    Quote Originally Posted by dan
    you have the system:
     (1)W_r + (1)W_f =17700
     (.874) W_r + (-1)W_f =0
    add the coefficients to get
     (1+.874)W_r + (1+-1)W_f = 0+17700
    or  (1.874)W_r=17700
    let me know if that made sence...

    dan
    oh ya it made sense.
    this is so clear. and its better
    now i got the whole idea of it!!
    Follow Math Help Forum on Facebook and Google+

  15. #30
    Junior Member
    Joined
    Aug 2006
    Posts
    38
    hi there i have problem with this word problems

    Set up appropriate systems of two linear equations in two unknowns and then solve the systems by determinants. all numbers are accurate to at least two significant digits.


    (A) A shipment of 320 cell phones and radar detectors was destroyed due to a truck accident. on the insurance claim, the shipper stated that each phone was worth $110, each detector was worth $160, and their total value was $40700. how many of each were in the shipment?

    (1) $110 + $160 = $40700<--------is the first equation right??
    (2) ??????????????????????


    was wondering is there a way to master these word problem?
    Follow Math Help Forum on Facebook and Google+

Page 2 of 3 FirstFirst 123 LastLast

Similar Math Help Forum Discussions

  1. System of linear equations.
    Posted in the Algebra Forum
    Replies: 6
    Last Post: October 29th 2010, 03:48 PM
  2. Non-linear system of two equations
    Posted in the Algebra Forum
    Replies: 5
    Last Post: October 3rd 2010, 01:05 PM
  3. System of linear equations.
    Posted in the Algebra Forum
    Replies: 5
    Last Post: August 9th 2010, 11:03 PM
  4. Replies: 2
    Last Post: April 20th 2010, 03:26 PM
  5. System of non-linear equations
    Posted in the Algebra Forum
    Replies: 4
    Last Post: May 4th 2009, 08:18 PM

Search Tags


/mathhelpforum @mathhelpforum