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More math linear equation help?

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I'm looking at this graph where I see a line AB with the points (-2,2) and (2,8). Then I have to do the following:

a) Find the length of AB

b) Find the midpoint of AB

c) Write an equation for the line going through AB

I don't understand how to do part a and c, so could somebody help me there? And would the midpoint of AB be (0,4)?

  • More math linear equation help? -

    Think of the two points as lying on the ends of the diagonal of a rectangle (or, the hypotenuse of a right triangle).

    So, the length d^2 = 4^2+6^2 = 52
    d = 2√13

    The midpoint is the average of the endpoints: (0,5)

    The slope of the line is constant, and between any two points, is ∆y/∆x

    We have two points, so the slope is 4/6 = 2/3

    Now we have a slope (2/3) and a point (-2,2). For any other point (x,y) on the line, the slope remains constant, so

    (y-2)/(x+2) = 2/3
    y-2 = 2/3 (x+2)

    You can massage that into any other form you need.

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