Question

Write the equation of a line that is perpendicular to y= -2/7 x+9 and that passes through the point (4,-6)

Answer 1

y=7/2x -20

Explanation:

TRUST ME

Answer 2

y =
`(7)/(2)` x - 20

Explanation:

The equation of a line in slope- intercept form is

y = mx + c ( m is the slope and c the y- intercept )

y = -
`(2)/(7)` x + 9 ← is in slope- intercept form

with slope m = -
`(2)/(7)`

Given a line with slope m then the slope of a line perpendicular to it is

`m_(perpendicular)` = -
`(1)/(m)` = -
`(1)/(-(2)/(7) )` =
`(7)/(2)`, thus

y =
`(7)/(2)` x + c ← is the partial equation

To find c substitute (4, - 6) into the partial equation

- 6 = 14 + c ⇒ c = - 6 - 14 = - 20

y =
`(7)/(2)` x - 20 ← equation of perpendicular line