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Math Help - Need some help with graphing a system of equations

  1. #1
    aim
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    Need some help with graphing a system of equations

    I need to graph a system of equations. I'll write it down below. Sorry in advance if it's hard to understand.

    4x - 3y = 5 (first half of the system)
    -3y = -4x + 5
    -3y/-3 = -4x/-3 + 5/-3
    y = 4/3x - 5/3
    m=4/3 b=- 5/3

    y = 4/3x - 7/3 (second half of the system)
    m=4/3 b=- 7/3

    Have I done everything right so far? What do I do next?
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  2. #2
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    Quote Originally Posted by aim View Post
    I need to graph a system of equations. I'll write it down below. Sorry in advance if it's hard to understand.

    4x - 3y = 5 (first half of the system)
    -3y = -4x + 5
    -3y/-3 = -4x/-3 + 5/-3
    y = 4/3x - 5/3
    m=4/3 b=- 5/3

    y = 4/3x - 7/3 (second half of the system)
    m=4/3 b=- 7/3

    Have I done everything right so far? What do I do next?
    Yes. But are you able to use what you've done to draw the graphs of these two lines?

    Personally, I draw a line by finding two points on it - usually the x-intercept and the y-intercept.
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  3. #3
    aim
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    Quote Originally Posted by mr fantastic View Post
    Yes. But are you able to use what you've done to draw the graphs of these two lines?

    Personally, I draw a line by finding two points on it - usually the x-intercept and the y-intercept.
    I've never had to graph a system of equations involving fractions so I'm not really sure.
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  4. #4
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    Quote Originally Posted by aim View Post
    I've never had to graph a system of equations involving fractions so I'm not really sure.
    So ....?

    4x - 3y = 5:

    x-intercept: Substitute y = 0 and solve for x. x = 5/4. Mark it on the x-axis.
    y-intercept: Substitute x = 0 and solve for y. y = -5/3. Mark it on the y-axis.

    Draw a line passing through the x-intercept and the y-intercept. Done.

    Why should fractions cause problems?
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  5. #5
    aim
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    Quote Originally Posted by mr fantastic View Post
    So ....?

    4x - 3y = 5:

    x-intercept: Substitute y = 0 and solve for x. x = 5/4. Mark it on the x-axis.
    y-intercept: Substitute x = 0 and solve for y. y = -5/3. Mark it on the y-axis.

    Draw a line passing through the x-intercept and the y-intercept. Done.

    Why should fractions cause problems?
    I've never had to graph a y-intercept that was a fraction before. Should I use the numerator as the rise and denominator as the run? Or?
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  6. #6
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    Quote Originally Posted by aim View Post
    I've never had to graph a y-intercept that was a fraction before. Should I use the numerator as the rise and denominator as the run? Or?
    The y-intercept is where the line cuts the y-axis. It's a number. You mark it in on the y-axis.

    The x-intercept is where the line cuts the x-axis. It's a number. You mark it in on the x-axis.

    Have you been taught what a y-intercept is and what an x-intercept is?
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  7. #7
    aim
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    Quote Originally Posted by mr fantastic View Post
    The y-intercept is where the line cuts the y-axis. It's a number. You mark it in on the y-axis.

    The x-intercept is where the line cuts the x-axis. It's a number. You mark it in on the x-axis.

    Have you been taught what a y-intercept is and what an x-intercept is?
    4x - 3y = 5 (first half of the system)
    -3y = -4x + 5
    -3y/-3 = -4x/-3 + 5/-3
    y = 4/3x - 5/3
    m=4/3 b=- 5/3

    b is the y-intercept, right? Well, for the questions I've had so far b has always equaled a whole number. If it was b=7 I would put a point on (0,7). The problem is that I don't know how to graph the y-intercept when it's a fraction. Does that make sense?
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  8. #8
    aim
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    I still need help for this, if anyone is willing. Sorry to be naggy, but I really need help understanding how to use these fractions when graphing.

    PS: I'm totally clueless, so if you decide to help me please be patient.
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