math help ! solving elimination in non standard form!!?

9x - 3y = 63

7x - 3y = 45

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  • ?
    Lv 7
    8 years ago

    9x - 3y = 63

    7x - 3y = 45.........Multiply by - 1

    9x - 3y = 63

    -7x + 3y = -45

    *****************ADD

    2x = 18

    x = 9

    9(9) - 3y = 63

    81 - 3y = 63

    -81........- 81

    - 3y = - 18

    y = 6

    ( 9 , 6 ) ......................ANSWER

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  • Anonymous
    8 years ago

    9x-3y=63

    7x-3y=45

    9x-3y=63

    -7x=3y=-45

    (-3y and +3y gets canceled and the rest we solve it)

    it becomes:-

    2x= 18

    then,

    x=18/2=9

    therfore,

    x=9

    to find y(substitute the value of x in any one eq.)

    7x-3y=45

    7(9)-3y=45

    63-3y=45

    -3y=-18

    y=6

    therefore the value of:

    x=9 , y=6

  • Moon
    Lv 7
    8 years ago

    9x - 3y = 63 ........eq1

    7x - 3y = 45 .........eq2

    -----------------------------

    2x = 18 ..............eq1 - eq2

    x = 9 ..................................... x solved

    9x - 3y = 63 ........eq1

    81 - 3y = 63

    -3y = 63 - 81 = -18

    y = 6 ....................................... y solved

    check:

    7x - 3y = 45 .........eq2

    7*9 - 3*6 = 45

    63 - 18 = 45 ........................ true!!!

    Our answer is:

    (x,y) = (9, 6)

    .......

  • Como
    Lv 7
    8 years ago

    9x - 3y = 63

    -7x + 3y = - 45______ADD

    2x = 18

    x = 9

    63 - 3y = 45

    18 = 3y

    y = 6

    x = 9 , y = 6

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  • 8 years ago

    -1 (9x-3y=63

    7x-3y=45

    -9x+3y=-63

    7x-3y=45

    --------------

    -2x=-18

    x=9 if x=9 y=6

  • 8 years ago

    9x - 3y = 63

    7x - 3y = 45

    ------------------ (subtract)

    2x = 18

    x = 9

    and if x =9, then 9(9) - 3y = 63

    81 - 63 = 3y

    18 = 3y

    y = 6

    (9 , 6) = (x , y)

    check in the other equation:

    7(9) - 3(6) = 63 - 18 = 45 checks

  • 4 years ago

    the 1st ingredient to do is to get the equations into familiar variety: 6x -6y = 6 -4x + 8y = 4 divide out the 6 from the 1st equation and divide the 2nd equation through four. you will then have: x - y = a million -x + 2y = a million upload the two equations. the x's cancel out and you have: 2y - y = 2 y = 2 exchange y=2 into the 1st equation to get x - 2 = a million x = 3

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