Math Cumulative Review: Find the equation of a Line

[Mathlete2]

Hey there! Currently struggling through a cumulative review, so I will posting a lot more questions.

An equation of a line perpendicular to the line represented by the equation y= -1/2x-5 and passing through (6, -4) is

1) y= -1/2x + 4
2) y= -1/2x - 1
3) y= 2x + 14
4) y= 2x - 16

I know it's not 1 or 2 because perpendicular lines have to be negative reciprocals. What I don't know is how to figure out whether the answer is 3 or 4.

 

[skeeter]

point-slope form ...

$y-y_1 = m_{\perp}(x -x_1) \implies y-(-4) = 2(x-6)$

simplify

 

[HallsofIvy]

Hey there! Currently struggling through a cumulative review, so I will posting a lot more questions.

An equation of a line perpendicular to the line represented by the equation y= -1/2x-5 and passing through (6, -4) is

1) y= -1/2x + 4
2) y= -1/2x - 1
3) y= 2x + 14
4) y= 2x - 16

I know it's not 1 or 2 because perpendicular lines have to be negative reciprocals. What I don't know is how to figure out whether the answer is 3 or 4.

You are also told that when x= 6, y= -4. What do you get for y when you put x= 6 in either (3) or (4)?