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The line L: 4x - 5y + 20 = 0 cuts the x - axis at A and cuts the y - axis at B. find the equation of a line perpendicular to L and passing through the origin.​

User Andy Song
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Answer:

  • x-intercept: (-5, 0)
  • y-intercept: (0, 4)
  • perpendicular: 5x +4y = 0

Explanation:

Each of the intercepts is found by setting the other variable to zero and solving for the intercept value.

x-intercept

4x -5·0 +20 = 0

x +20/4 = 0 . . . . . divide by the coefficient of x

x = -5 . . . . . . . . . . add -5

The x-intercept point is (-5, 0).

__

y-intercept

4·0 -5y +20 = 0

y +20/-5 = 0 . . . . . divide by the coefficient of y

y = 4 . . . . . . . . . . . add 4

The y-intercept point is (0, 4).

__

The perpendicular line is found by swapping the x- and y-coefficients, negating one of them. You want the leading coefficient positive, so the equation becomes ...

5x +4y = (some constant)

The constant is chosen according to the point you want on the line. For a line through the origin, the constant is zero.

5x +4y = 0 . . . . perpendicular line

The line L: 4x - 5y + 20 = 0 cuts the x - axis at A and cuts the y - axis at B. find-example-1
User Asad Saeeduddin
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4.8k points