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Use the Substitution method to solve the system of equations.?

Use the Substitution method to solve the system of equations.

x + y = -4

x - y = 2

7 Answers

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  • Como
    Lv 7
    1 decade ago
    Favorite Answer

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    2x = - 2

    x = - 1

    - 1 + y = - 4

    y = - 3

    x = - 1 , y = - 3

  • 1 decade ago

    Solve one of the equations for either x or y and substitute that into the second equation thereby eliminating one of the variables.

    For example: 2nd equation could become x = y+2. Substituting this into the 1st eqn you get

    (y +2) +y = -4 Solve this for y and you get y=-3

    Therefore x = y+2 = -3+2 = -1

  • 1 decade ago

    Solve for one of the unknowns first.

    x-y+y=2+y, simplified to x=y+2, since we know x equals y+2, we can replace "x" it in the first equation.

    (y+2)+y=-4

    simplified to:

    2y + 2 = -4

    subtract 2 from each side gives you:

    2y = -6

    Divide both sides by 2 gives you:

    y = -3.

    We can now subsitute y in either equation to solve for x.

    x + (-3) = -4 , x = -1

    We can test it in the other equation.

    (-1) + (-3) = -4, which is true!

    x = -1, y = -3

  • 1 decade ago

    from eq 2: x = y+2

    (y+2) + y = -4

    2y = -6

    y = -3

    x = -3 + 2 = -1

    (-1, -3)

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  • Anonymous
    1 decade ago

    from (1) you have

    x=-(4+y)

    replace in (2)

    -4-y-y=2

    2y=-6

    y=-3

    x=-1

  • 1 decade ago

    x=-4-y

    -4-y-y=2

    -4-2y=2

    -2y=6

    y=-3

    -3+x=-4

    x=-1

  • Anonymous
    1 decade ago

    Pshhhhh just graph it.

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