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Algebra

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What is the standard form of the equation of the line passing through the point (-1,-2) and perpendicular to the line y= - 2/3x - 1?

a. 3x-2y=-1
b.3x-2y=1
c.3x+2y=1
d.3x+2y=-1


I don't understand, can anyone help me please?

  • Algebra - ,

    Would this be B?

    3(-1) - 2(-2) = 1
    (-3) - (-4) =1
    1 = 1

  • Algebra - ,

    Yes.

    However, I don't think you understand why. Just checking to see which of the lines contains your point is not enough.

    The line y = -2/3x - 1 has slope -2/3.

    Any line perpendicular to that line has slope -1/(-2/3) = 3/2.

    So, now you have a slope and a point.

    Using the point-slope form a line,

    y-(-2) = 3/2 (x-(-1))

    y+2 = 3/2 (x+1)
    2(y+2) = 3(x+1)
    2y + 4 = 3x + 3
    3x - 2y = 1

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