1. #1
    Unregistered

    Explain the Logic to find x and y from the following equations?

    hello,
    how to find x and y from these two,
    5x+3y=10
    3x+5y=20 ??





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  3. #2
    Giraffe
    Join Date
    Jun 2012
    Posts
    234

    Re: Explain the Logic to find x and y from the following equations?

    The logic is simple.The basic logic is to first find the value of either x or y using the two given equation.This can be achieved by-
    1.Multiply the entire 1st equation with 3.

    2.Multiply the entire 2nd equation with 5.
    The resultant equations become-
    15x+9y=30
    15x+25y=100

    3.Now subtract equation 1st from 2nd,we get:
    15x+25y=100
    -15x-9y=-30
    It becomes->16y=70
    Thus,y=70/16=4.375

    4.Now,put the value of y on 1st equationn to get x.
    5x+3*4.375=10
    =>x=10-13.125/5
    =>x=0.625




  4. #3
    raki!!!
    Join Date
    Aug 2012
    Location
    hyderabad
    Posts
    280

    Re: Explain the Logic to find x and y from the following equations?

    let 5x+3y=10 be equation1
    & 3x+5y=20 be equation2

    multiply equation1 with 3 and equation2 with 5

    substract the resultant equations and find value of y

    the substitute value of y in any of the 2 equations and find value of x

    thus we found x,y values

  5. #4
    Anupama Niranjana
    Join Date
    Jul 2012
    Posts
    39

    Re: Explain the Logic to find x and y from the following equations?

    Hi Dear,
    The logic is very easy.
    step 1- let the 5x+3y=10 be equation 1
    & 3x+5y=20 be equation 2

    step 2- Multiply equation 1 with 3 and equation 2 with 5,then the two equations will be:
    15x+9y=30
    15x+25y=100

    step 3- Now equation 2 - equation 1,we get
    y=4.375

    step 4- Substitute the value of y in any of the two equation and you will get the value of x i.e.
    x=0.625.

  6. #5
    lakshmi dhana
    Join Date
    May 2012
    Location
    kk
    Posts
    1,299

    Re: Explain the Logic to find x and y from the following equations?

    5x+3y=10
    3x+5y=20

    >>make the coefficient of one variable to be same

    >>Cancel them by adding/subtracting two equations

    >>Find out the value of one variable

    >>Substitute it in any one of the equation and find out the other variable...

    Ans:x=0.625,y=4.375

  7. #6
    sriniwaas
    Join Date
    Oct 2012
    Posts
    69

    Re: Explain the Logic to find x and y from the following equations?

    hi it is simple,
    5x+3y=10.........(1)
    3x+5y=20..........(2) let these two equations

    multiply equation 1 with number 3 and
    multiply equation 2 with number 5
    then it will be 15x + 9y=30............(1)
    15x+25y=100..........(2)
    now subtract equation 2 with 1 you get 6y=70
    now you can find the 'y' value as y=11.67
    substitute the Y value in equation 1or2.
    if equation ........(1)
    5x+3(11.67)=10
    5x+35=10
    5x=10-35
    5x=-25
    x=-25/5
    x= -5
    you can check the answer by substituting the X,Y values in equation 1or2
    the same procedure for equation..............(2)


    all the best

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