Question

The equation of line WX is y = −2x − 5. Write an equation of a line perpendicular to line WX in slope-intercept form that contains point (−1, 1).

y = 1 over 2 x − 3 over 2
y = − 1 over 2 x − 3 over 2
y = 1 over 2 x + 3 over 2
y = negative 1 over 2 x + 3 over 2

Answer 1

third option

Explanation:

The equation of a line in slope- intercept form is

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

y = - 2x - 5 ← is in slope- intercept form

with slope m = - 2

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

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

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

To find c substitute (- 1, 1) into the partial equation

1 = -
`(1)/(2)` + c ⇒ c = 1 +
`(1)/(2)` =
`(3)/(2)`

y =
`(1)/(2)` x +
`(3)/(2)` ← equation of perpendicular line