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Posted by on Saturday, October 31, 2009 at 9:00pm.

how do you Find the slope of graphs and linear equations???
like (3,5) and(2,-2)
how do i solve that

  • alegebra 1 - , Saturday, October 31, 2009 at 9:09pm

    Given two points, the slope is easy: it's the difference in the ys divided by the differences in the xs.

    Just be careful to get the numbers in the right order and careful of the signs.

    For example, (3,5) and(2,-2)

    x1=3
    x2=2

    y1=5
    y2=-2

    So the slope is
    (y1 - y2)/(x1 - x2)

    = (5 - (-2)) / 3 - 2
    = (5 + 2) / 1
    = 7

    We can go on from there to get the equation of the line:

    y = mx + c , where m is the slope

    y = 7x + c in this case

    But what is c? Well, we substitute any point on the line for x and y, and

    5 = 7*3 + c

    5 = 21 + c

    c = -16

    So the line is

    y = 7x - 16

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