Write the equation of the line which passes through (2, 1) and is perpendicular to x = –2. (1 point)?

need help understanding this equation step by step


but i need help solving it step by step

5 Answers

  • 8 years ago
    Favorite Answer

    Hi there --

    Two things to keep in mind when solving these -- first is how to find the equation of a line, given its slope and point on the line; second how to find the slopes of perpendicular lines.

    In this problem, we need to recognize that the slope of x = -2 is undefined, as it's a vertical line. This means that its slope which is generally known to be the negative reciprocals (for defined nonzero numbers) ends up being zero for the case of a line with undefined slope. All this means is that lines perpendicular to a vertical line are always horizontal and, therefore, have slope m = 0.

    Given this slope, now derive the equation of the line from slope-intercept form:

    y = mx + b,

    using m = 0, and the point (2,1) as an instance of x, y -- to find b:

    1 = 0*1 + b;

    so b = 1.

    Thus our equation is y = 0x + 1 or just y = 1.

    I put together a short video tutorial which further illustrates this solution, and cited it as a source below. We hope it is helpful.

  • Bob B
    Lv 7
    8 years ago

    The line for the equation x = -2 is a vertical line that's drawn two units to the left of the y-axis.

    A line perpendicular to that one must be horizontal.

    A horizontal line passing through point (2, 1) has a constant y value of 1. Its equation is:

    y = 1

  • Brenda
    Lv 7
    8 years ago

    because your line is x=-2 , which is a vertical line , then the perpendicular line to it has to be an horizontal line which means y=k

    because the given point is (2,1) , then the line perpendicular to x=-2 is y=1

  • 8 years ago

    x = -2 is a vertical line so we want a horizontal line through (2, 1). That line is y = 1.

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  • 8 years ago

    Exactly what Iggy said!

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