Question

What is the equation of the line in slope-intercept form? the line perpendicular to

y = 1/3x + 5 through (2, 1)
A. y = 1/3x + 7

B. y = -1/3x + 7

C. y = -3x + 7
D. y = 3x + 7

Answer 1

so lets find the slope perpendicular to this equation first

Answer 2

dontknownomth is this the same process?

Answer 3

or do i need two y's and two x's

Answer 4

the last problem you had two points so this process is different

Answer 5

so whats your slope in this equation?

Answer 6

y=1/3x=5
i believe i could type that into desmos and see the pints it goes through?

Answer 7

points*

Answer 8

well now your looking for the perpendicular line

Answer 9

i meant to put y=1/3x+5 btw
and what process would i take to find this out?

Answer 10

Here's a clear example

Answer 11

y = 1/3x + 5 through (2, 1)
STEP #1--So what is the your slope?

Answer 12

that made me more confused

Answer 13

1/3

Answer 14

okay STEP #2- Find your perpendicular slope
Do you know how to find it?

Answer 15

nope

Answer 16

To find your perpendicular slope is to "flip" your original slope and change the sign

Answer 17

so 1/3 flipped is?

Answer 18

3/1

Answer 19

Yes!! and no change the sign to have your perpendicular slope

Answer 20

now*

Answer 21

change the sign?

Answer 22

so its + 3 but if we change the sign what will it be?

Answer 23

-3/1

Answer 24

well -3

Answer 25

Yes! so our perpendicular slope is -3 to the original slope 1/3

Answer 26

so to find the perpendicular slope we "flip" and change the sign

Answer 27

which we just did

Answer 28

right

Answer 29

okay now comes STEP #3 We plug our new slope into the point slope formula
Do you know what the point slope formula is?

Answer 30

no clue

Answer 31

Point Slope Formula:
\[y-y _{1}=m(x-x _{1})\]

Answer 32

so whats our \[(x _{1},y _{1}) \] & m

Answer 33

y-1=-3(x-2)

Answer 34

Correct!!! now solve for y

Answer 35

would i just be left with -3?

Answer 36

where does the +5 come in

Answer 37

nope okay i'm going to help you solve
so we want what variable alone?

Answer 38

the +5 has nothing to do with this perpendicular equation even though its part of the original equation

Answer 39

okay

Answer 40

so you found this equation so we want y alone
so what do we have to do first with the -3?
y-1=-3(x-2)

Answer 41

move beside (x-2)

Answer 42

you mean distribute to (x-2)

Answer 43

distribute meaning?

Answer 44

-3-2?

Answer 45

(-3-2)

Answer 46

Distributing=multiplying the number exactly outside the parenthesis into the parenthesis