Question

Find the x-intercept of the line that passes through (-3,4) and is perpendicular to the graph of x-2y=7

Answer 1

x - intercept = - 1

Explanation:

the equation of a line in slope- intercept form is

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

given

x - 2y = 7 ( subtract x from both sides )

- 2y = - x + 7 ( divide through by - 2 )

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

with slope m =
`(1)/(2)`

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

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

y = - 2x + c ← is the partial equation of the perpendicular line\to find c substitute (- 3, 4 ) into the partial equation

4 = 6 + c ⇒ c = 4 - 6 = - 2

y = - 2x - 2 ← equation of perpendicular line

to find the x- intercept let y = 0 into the equation and solve for x

- 2x - 2 = 0 ( add 2 to both sides )

- 2x = 2 ( divide both sides by - 2 )

x = - 1

the x- intercept of the perpendicular line is - 1 or (- 1, 0 )