Question

Write an equation in slope-intercept form for the line described.

1. Perpendicular to y = - 4 x + 1, pass through ( - 8 , - 1 )

2. Parallel to y = 2/ x + 6, y-intercept at -2

3. Parallel to y = 9 x + 3. passes through ( 6, 7)

Answer 1

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

`y = 2x - 2`

`y = 9x - 57`

Explanation:

If 2 lines are perpendicular the slopes multiplication is - 1.

If 2 lines are parallels the slopes are the same

1. slope : - 4 then

-4 * x = - 1

x = 1/4

now for the y-intercept you replace the point in the line (8,-1)

y = 1/4 x + b

-1 = 1/4 * 8 + b

-3 = b

with y-intercept the equation is:

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

2. y = 2/x +6 isnt a line so I assume is y = 2*x +6

In this case the line you are looking for has the same slope and y - intercept is already given

`y = 2x - 2`

3. Again same slope, because the lines are parallels and you have to replace (6,7) to get the y-intercept

y = 9x + b

6 = 9*7 + b

b = - 57

`y = 9x - 57`