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Math Help - I really need help (Algebra 2)

  1. #1
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    I really need help (Algebra 2)

    okay, so i suck at math go ahead and laugh. but i really need help.
    I need variables x, y, and z.

    the three equations that x, y, and z must work for are:
    -2x + y +6z = 1
    3x + 2y + 5z = 16
    7x +3y - 4z = 11
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  2. #2
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    Quote Originally Posted by dropkikkmarc71 View Post
    okay, so i suck at math go ahead and laugh. but i really need help.
    I need variables x, y, and z.

    the three equations that x, y, and z must work for are:
    -2x + y +6z = 1
    3x + 2y + 5z = 16
    7x +3y - 4z = 11
    see the last post in this thread ...

    http://www.mathhelpforum.com/math-he...equations.html
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  3. #3
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    I'm assuming you know how to do a system of equations with only two variables, so all you need to do is reduce this system to do that.

    I'll label them for convenience.

    A) -2x + y +6z = 1
    B) 3x + 2y + 5z = 16
    C) 7x +3y - 4z = 11

    All you need to do multiple and subtract to reduce.

    We'll so A - B because it's just he one that occurred to me first. We're getting rid of y's, so we need the constants for y to be the same. Multiple A by 2, so you get:

    -4x + 2y + 12z = 2

    Now subtract B and you'll have an equation with just x and z.

    A-2B = -7x - 3z = -14

    Now you need to make a second one. Because it's easiest, do A-C. After that you'll have two equations with just x and z, and you can treat it like a simpler system of equations. Solve for x and z, and then plug those values into any of the equations to find y.

    There's a few variations you can take in that process, but that's probably the easiest.
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