Question

What is the equation of the line passing through (–3, –9) and parallel to the line y = x + 6 in standard form?

Answer 1

Sorry, wrong question,
What is the equation of the line passing through (–6, 1) and perpendicular to the line y = –3x + 1 in slope-intercept form?

Answer 2

Get the gradient of the line y = -3x + 1 first. What is it?

Answer 3

Gradient?

Answer 4

Slope... Sorry

Answer 5

3 :D

Answer 6

The slope is -3 to be more precise. Now, what will be the slope for a line that is perpendicular to the one having a slope of -3?

Answer 7

I can find that out by graphing, yet it seems inefficient (time wise). Is there a method for me to find that out without having to do that?

Answer 8

Well, basically, when two lines are perpendicular to each other, their slopes are related. The slope of the perpendicular line is the negative reciprocal of the referenced line.

So, if the slope of a line is x, the slope of the line perpendicular to it will be - (1/x)

Answer 9

so the slope perpendicular to -3 would then its reciprocal? (3)

Answer 10

It would be the negative reciprocal, which is (1/3)

Answer 11

Oh, I see. So I have my slope. So for me to find the equation, I now have to find y-intercept. Does this mean I have to substitute the x and y with the point I have?

Answer 12

That's exactly what you do since you have a general equation for your line, which will be like

y = (x/3) + C, where C is the intercept. You just substitute the coordinates that was given to you to determine the intercept as you've said.

So what's the equation you get then?

Answer 13

ohh now I got it. Would my answer be y=1/3x +3?

Answer 14

YES! Nice job :)

Answer 15

thanks for your help :D

Answer 16

My pleasure... :)