Question

Consider the line y : 3x-8.

2
Find the equation of the line that is perpendicular to this line and passes through the point (8,
- 4).
Find the equation of the line that is parallel to this line and passes through the point (8, -4).

Answer 1

Explanation:

Perpendicular line will have a slope that is the negative reciprocal so slope of 3 becomes -
`(1)/(3)`.

then use point slope:

y - y = m(x - x)

Use the 2 points (8, -4)

y - -4 = -
`(1)/(3)` (x - 8)

y + 4 = -
`(1)/(3)` (x - 8)

y + 4 = -
`(1)/(3)`x +
`(8)/(3)`

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

y = -
`(1)/(3)`x -
`(4)/(3)`

Parallelline will have the same slope m = 3.

use point slope again

y - -4 = 3(x -8)

y + 4 = 3x - 24

y + 4 -4 = 3x - 24 -4

y = 3x -28