Question

Algebra I Help? Parallel and Perpendicular Lines?

Answer 1

Hold on a sec.

Answer 2

The equation of a line is shown below.\[y=-\frac{ 1 }{ 3 }x-24\]What is the equation of a line which is perpendicular to this line and passes through (1, 27)

a. y = 3x - 24
b. y = 7x - 24
c. y = 7x + 24
d. y = 3x + 24

Answer 3

bom dia
kewlgeek ^_^

Parallel and perpendicular, it's all to do with slopes... that said, what's the slope of your given line?

Answer 4

Uh...3 over 1? ._.

Answer 5

You're not too sure of yourself...are you? :D

Answer 6

When you have the line given in THIS form:
\[\Large y = \color{blue}mx +b\]
the value \(\large \color{blue}m\) is the slope :)

Answer 7

T_T
I didn't read the lesson!
-crowd gasps-

Answer 8

Well I know THAT.

Answer 9

Don't worry, that's why I'm here, to DEAL with your behaviour >:)

Answer 10

Just kidding.
and lol, if you did know that, then what's the slope of this line:
\[\Large y = \color{blue}{-\frac13}x-24\]

Answer 11

The slope is 1 over 3 -duh.

Answer 12

Nope, it's -1/3
signs matter :)

Answer 13

OMGOMG IS IT:\[y=3x+24\]?????????????

Answer 14

Are you in any sort of hurry?

Answer 15

Well, can't lie to you, can I?
Yes it is.
How did you get it?

Answer 16

(I hate these multiple choice questions... they take away all the fun -_-)

Answer 17

Well I am so sorry for the late reply but my mom told me I had to go to lunch and it was such a short notice so I had to leave. Anyways I got it because I put everything opposite. the fraction got flipped and the subtraction sign got into a plus sign.

Answer 18

Still need help?

Answer 19

Well I do have one...

Answer 20

Sure thing...

Answer 21

Choose the equation of the line passing through the point (-1, 3) and perpendicular to:\[y=-\frac{ 1 }{ 3 }x+7\]
a. y = 3x - 12
b. y = 3x + 6
c. y = 3x - 6
d. y = 3x

Answer 22

Well, since they all have the same slope the first part of the question is easy.

Answer 23

Because if a line has a slope = "m"
Then a 2nd line perpendicular to that 1st line has a slope equal to

-1/m

Answer 24

So it would be C?

Answer 25

Not quite...

Answer 26

Since you know the slope must be "3", just plug in the "-1" and "3" in point slope form.

Answer 27

i.e.

y - 3 = 3(x - (-1))
and solve

Answer 28

Since, given a slope "m" and a point:
\[(x_{0}, y_{0})\]

Answer 29

The equation of the line comes from the formula:

\[y - y_{0} = m(x - x_{0})\]
and then simplifying so that all the terms besides "y" are on the lefthand side.

Answer 30

0.0

Answer 31

So I solve y - 3 = 3(x - (-1))?

Answer 32

Exactly!

Answer 33

Okay. So I distribute first. The equation is now:
y - 3 = 3x - 3

Answer 34

Wait.. look at the righthand side...

Answer 35

Because it's "-(-1)"

Answer 36

Sorry for the late reply. So it is -3?

Answer 37

Ok, so we have:

\[y - 3 = 3(x - (-1))\]

Answer 38

What's another way to write:
-(-1)?

Answer 39

+1??

Answer 40

Yeah!

Answer 41

So now rewrite that line I gave you
y -3 = 3(x-(-1))

Answer 42

y - 3 = 3x + 3?

Answer 43

Yeah, now just add three to both sides.

Answer 44

y = 3x + 6

Answer 45

WOOHOO!

Answer 46

Yay! I have another one (sorry)