Question

The equation of line CD is y = 3x − 3. Write an equation of a line perpendicular to line CD in slope-intercept form that contains point (3, 1).

Answer 1

y = 3x + 0
y = 3x − 8
y = negative 1 over 3x + 2
y = negative 1 over 3x + 0

Answer 2

I'm so lost :(

Answer 3

@Vijeya3

Answer 4

@gottennis121

Answer 5

Gee, I just became brain dead due to telling myself I'm done with school for the day. I know the perfect person to ask though. Please welcome, @mathmath333 !! Ok, you get the point. I'm sorry, I probably know this when I'm in the zone.

Answer 6

It's ok, thanks for referring me to someone, i really appreciate it!

Answer 7

No prob. I wish my hamster wheel was working, but a bit screechy. xD

Answer 8

Hahah

Answer 9

are you here?

Answer 10

Yep

Answer 11

okay first you have to work out the gradient of the second line
We know its perpendicular to the first line which means their gradients follow the property
\[m1 *m2 = -1\]
Using this property can you calculate the gradient of the next line?

Answer 12

Do I plug in the coordinates (3,1)

Answer 13

no you have to plug in the gradient of the first line
m means gradient
m1 means gradient of first line
m2 means gradient of second line

Answer 14

How do i find the gradient? Haven't heard that word used in math

Answer 15

gradient also means slope of a line

Answer 16

now can you figure it out?

Answer 17

well attach the doc on plz so i can see original problem

Answer 18

Hmmm so I have to get the slope of the coordinates first?

Answer 19

@Sohal Here you go

Answer 20

slope of the line is the constant attached to x

Answer 21

Oh okay, so 3?

Answer 22

yes

Answer 23

Making the gradient of the first line 3?

Answer 24

plug it in the equation i gave you to find out the slope of the other line

Answer 25

it would give me 3 again

Answer 26

no it would give you
3 * m2 =-1
m2 = -1/3

Answer 27

Ohhh so because we dont have m2 we reverse the equation by divding 3 by -1

Answer 28

Giving us -3

Answer 29

now you have the slope (or gradient or change in y/ change in x)
use it in the equation
y = mx +c
where m is the m2 and c is the constant you will find by plugging in the x = 3 and y =1

Answer 30

Hmm im a little lost again sorry

Answer 31

y = mx +c is the equation you will use now
plug the value of m2 in its place.
WHats the equation now?

Answer 32

y=-3+c

Answer 33

y = -1/3 x +c

Answer 34

\[y = -1/3 *x +c\]

Answer 35

now input the value x =3 and y =1 and find out the value of c

Answer 36

Hm okay, ill try that out

Answer 37

1=-1/3 3 + c

Answer 38

So what would that make C?

Answer 39

1 = -1 +c
c =2
y =( -1/3 )x +2

Answer 40

Ohhh okay I get it, thanks!!

Answer 41

good