Question

find the equation of the line that passes through the points (3,6) and (-5,9)

Answer 1

y=mx+b to find m use

\[\huge m = \frac{ y_{2}-y _{1} }{ x _{2}-x _{1} }\]

Answer 2

m represents your slope

Answer 3

Anyways, gtg game of thrones is on, gl!

Answer 4

how is that the equation

Answer 5

If you input your x and y point into that equation, it will give you the slope of the line you are trying to find.

Answer 6

thats just the slope not equation

Answer 7

Or if you prefer, you could use the point-slope formula:

\[\Large y-y_{1}=m(x-x_{1})\]

Answer 8

how??

Answer 9

so my points are 3,6 and -5,9

Answer 10

Yes, now assign them x and y values. So x=3 y=6 and then do the same for the other set. Then you can input these into the point-slope formula to find the slope of the line you are trying to find.

Answer 11

x1 is 3 and y1 is 6?

Answer 12

Sure. Then let x=-5 and y=9. The important thing here is that you keep the sets of coordinates together. (x1,y1) and (x,y). Now try putting these numbers into the point-slope equation that was posted above.

Answer 13

ok here is what i have

9-6 =m(-5-3)

Answer 14

Excellent. Now solve for m (this is giving you the slope).

Answer 15

-0.375

Answer 16

So what we have now is the slope of our line (m=-0.375 or -3/8) and we know that the line intersects the points (3,6) and (-5,9). We actually only need to know 1 set of coordinates. So pick the set and enter that, and the slope, into the point-slope form.

Answer 17

how i dont get it

Answer 18

The number you just solved for (-0.375) is the slope of the line. It tells you the rise (the change in y values) divided by the run (the change in x values).

Answer 19

y-3=0.375(x-6)

Answer 20

Yes. Now you could leave the equation like that, or you might want to solve for y so that it is in slope-intercept form (y=mx+b).

Answer 21

Does your question specify how they want you to answer the question?

Answer 22

all it says is this:

Find the equation of the line that passes through the points (3,6) and (-5,9)

Answer 23

They probably want you to write it in y=mx+b form (at least that is what I used to do). So solve your equation for y and you should be done! :)

Answer 24

how would i solve for y?

Answer 25

By solving for y I just mean do some algebra and move the equation so that y is isolated on the left hand side.

Answer 26

this is confusing for me sorry i probably sound like an idiot haha

Answer 27

No you don't! This stuff can be confusing. Just try to understand each step as opposed to just plugging in numbers into random formulas and you should be fine!

Answer 28

so move y to the other side i would take y and put it like this

-3= 0.375(x-6)-y

Answer 29

I think we made a mistake

Answer 30

ok

Answer 31

Okay when you put your coordinates and slope into the point-slope equation, you mixed up the x and y values. So instead of y-3=-0.375(x-6) it should be y-6=-0.375(x-3)

Answer 32

Because the equation is y-y1=m(x-x1)

Answer 33

ok so -6=0.375(x-3)-y

Answer 34

Yup but you do not need to move the y over to the right hand side. We want to isolate y (which means it will say y=.....)

Answer 35

So try adding the 6 to both sides instead

Answer 36

what do i do with the (x-3)

Answer 37

Try multiplying it by the -0.375

Answer 38

6.375(x-3)

Answer 39

Ah, there is a bit of an algebra mistake there

Answer 40

y-3=-0.375(x-6)

add 3 to both sides

y=-0.375(x-6)+3

Answer 41

You cannot add the -0.375 and the 3 together directly because the -0.375 is being multiplied by the (x-6)

Answer 42

so would it be -6+3?

Answer 43

Nope! the -6 is in the brackets, you can simply add the +3 to the end of the equation.

Answer 44

so that is the whole equation

Answer 45

y=-0.375(x-6)+3

Answer 46

Yes, but to answer in slope-intercept form (y=mx+b) you should multiply the -0.375 by the (x-6)

Answer 47

1.875

Answer 48

I'm not sure what you did there.

Answer 49

ok so how do i multiply it? since i cant multiply x would i just multiply the 6

Answer 50

6 and -0.375

Answer 51

You can multiply it by the x. You would multiply it by the x and by the -6

Answer 52

i got 1.875

Answer 53

What did you do to get that answer?

Answer 54

-0.375 x 1 x 6