Question

Write an equation in slope-intercept form for the line passing through (–1, 10) and (5, 8).

A. y = 1/3x + 29/3
B. y = -1/3x - 29/3
C. y = -1/3x + 29/3
D. y = 1/3x - 29/3

I know the answer is C, but can someone please explain? Thanks

Answer 1

@math&ing001

Answer 2

slope= 8-10=-2 over 5--1 which is plus so equals 6. slope is -2/6 or -1/3

Answer 3

I know the slope, can you explain the rest?

Answer 4

y-1=-1/3(x-10) a negative times a negative is positive so thats where the +29 would come from

Answer 5

and the x by -1/3. And the 3 in 29/3. How about those?

Answer 6

wait thats not righ lol

Answer 7

What isn't right?

Answer 8

what i said wasnt right, im trying to figure out how we got to 29/3

Answer 9

Ok, but what is x?

Answer 10

the x is part of point slope form

Answer 11

y - y1 = m(x - x1)

Answer 12

So... still confused :/

Answer 13

If we filled it in it would be y-10=-1/3(x+1)

Answer 14

Oh, ok. How about 29/3?

Answer 15

ok 29/3 =9.66
so when we distribute the -1/3 over to +1 we get -1/3 again. now we add 10 to the other side to get in numerical terms 9.66

Answer 16

I still don't get how you got 9.66.. I'm sorry, can you explain more, this is very confusing.. :(

Answer 17

y-10=-1/3(x+1) --> distribute -1/3 to x and 1 to get y-10=-1/3x - 1/3. Now add 10 to the other side. 10+-1/3 essentially equals 9.66

Answer 18

9.66 is 29 over 3

Answer 19

Oh, that makes much more sense! thanks

Answer 20

do yu get it? I dont know how to get the 29/3 sorry

Answer 21

But you just got it.. 9.66, right?

Answer 22

@math&ing001 can you help?

Answer 23

yes 9.66 equals 29/3

Answer 24

@campbell_st can you help aswell?

Answer 25

Gemme a sec :)

Answer 26

Ok so you know how to find the slope, I'll just explain the rest. Formula for the slope gives: \[m=-\frac{ 1 }{ 3 }=\frac{ y-8 }{ x-5 }\] So: \[y-8=-\frac{ 1 }{ 3 }x+\frac{ 5 }{ 3 }\] And finally: \[y=-\frac{ 1 }{ 3 }x+\frac{ 29 }{ 3 }\]

Answer 27

Thank you :)

Answer 28

Welcome !

Answer 29

one question how did you go from 8 to 29

Answer 30

Ok, thank you both :)

Answer 31

Add 8 on both sides, then 8=24/3 so (24+5)/3=29/3.
yw @LovelyAnna

Answer 32

ohhh ok I see thanks again

Answer 33

@jigglypuff314

Answer 34

Hi Emily! Can you explain? Maybe I can understand from you a bit better :)

Answer 35

slope-intercept form: y = mx + b
when m = slope and b = y-intercept

so first find the slope between (–1, 10) and (5, 8)
\[slope = \frac{ rise }{ run } = \frac{ y _{2}-y _{1} }{ x _{2}-x _{1} }\]when given points (x1, y1) and (x2, y2)

Answer 36

I know the slope is -1/3, how about x and 29/3?

Answer 37

so you plug in m = -1/3
to get y = -1/3 x + b
then you would temporarily plug in a point to get the value of b

Answer 38

Mhm.. I understand it till there, how would you get b after that? I don't get that part..

Answer 39

so you plug in m = -1/3
to get y = -1/3 x + b
then you would temporarily plug in a point to get the value of b

so if you plug in point (-1, 10)
then you'll get 10 = (-1/3)(-1) + b
solve for b

Answer 40

Hmm.. confusing :/

Answer 41

what part do you not get? :)

Answer 42

How to solve for b

Answer 43

so if you plug in point (-1, 10)
then you'll get 10 = (-1/3)(-1) + b negative times negative equals positive
so 10 = 1/3 + b then subtract 1/3 from both sides
b = 10 - 1/3 10 = 30/3
\[so~~~b =\frac{ 30 }{ 3 } - \frac{ 1 }{ 3 }\]therefore b = 29/3

Answer 44

Oh, I see! thanks :)

Answer 45

you're welcome :)

Answer 46

There is another question I got wrong.. can you check it?

Answer 47

Select the pair of equations whose graphs are perpendicular.

A.
2x – 8y = 9
12x – 3y = 7

B.
2y = –3x + 5
2x + 3y = 4

C.
3x + 6y = 8
y = 2x – 8

D.
y = 2x – 7
x + y = 3

I choose B, but that isn't correct.. maybe C?

Answer 48

yeah C :)
because perpendicular slope is the flipped opposite

Answer 49

Thought so :) can you show me its equation?

Answer 50

what equation?

3x + 6y = 8 -> y = -1/2 x + 4/3
y = 2x – 8

-1/2 is the flipped opposite of 2

Answer 51

I mean how you could solve the question

Answer 52

solve the system of equations of ?
3x + 6y = 8 -> y = -1/2 x + 4/3
y = 2x – 8

y = y
so -1/2 x + 4/3 = 2x - 8
4/3 + 8 = 2x + 1/2 x
28/3 = 5/2 x
x = 56/15

Answer 53

Oooh, I get it! :D Thanks!

Answer 54

you're welcome :)

Answer 55

There is 1 last question I want to make sure of, you think you can help?

Answer 56

sure :)

Answer 57

Thanks :)

Graph the solution of the inequality.

14 ≤ 2t + 18 < 20

A. http://static.k12.com/calms_media/media/212500_213000/212712/1/530676c5e049c0298ebee00011ca070fcaecfd80/ALGTests_L2_S1_U9_Q9_A.gif

B. http://static.k12.com/calms_media/media/212500_213000/212716/1/5e480276ea3dbdc925988aeb5ef65a92316860fd/ALGTests_L2_S1_U9_Q9_D.gif

C. http://static.k12.com/calms_media/media/212500_213000/212713/1/556fb09d1057b44d43dd6c45f65425352134d2b7/ALGTests_L2_S1_U9_Q9_B.gif

D. http://static.k12.com/calms_media/media/212500_213000/212715/1/fc76a0269d4c8839c0f102b5950e8d166ceb65fa/ALGTests_L2_S1_U9_Q9_C.gif

This would be C, can you just explain how? Or maybe there is another answer?

Answer 58

2t + 18 ≥ 14 2t + 18 < 20
2t ≥ -4 2t < 2
t ≥ -2 t < 1

so t is between -2 and 1
with closed hole at -2
and open hole at 1

Answer 59

I don't get that.. but this is how I solved it:

14 ≤ 2t + 18 < 20

subtract 18 from both sides:

-4 ≤ 2t < 2

divide 2 by both sides

-2 ≤ t < 1

Is this correct?

Answer 60

yes :)

Answer 61

Alright, thanks Emily! =) I really appreciate your help!

Answer 62

you're welcome :)

Answer 63

Wish I could help you.. but your in a higher grade than me :(

Answer 64

lol, I just got a whole lot of stuff that I need help on xD
It's fine though :P I like helping people out with simple math <3

Answer 65

Oh.. sorry :(
If you say so.. that's what I like about you.. your soo helpful, and kind!

Answer 66

I try to be :P

Answer 67

Btw.. which equation is better for the last question, mine or yours?

Answer 68

You already are! :)

Answer 69

yours :P
and there are a few people on here that I really don't like helping >,<

Answer 70

You think so? I wonder why.. O.o
Really, like who? oh.. you mean people who use you to just answer there questions? :P

Answer 71

yeah... like they figured out the perfect way to just get answers out of me >,<
like posting a whole lot of questions at once, or guilt tripping me cuz they need to pass with a certain score within a certain amount of time...
I'm not gonna name names tho :P

Answer 72

Well, I post a lot of questions in one place.. you think I'm one of them? :O eeek!!

Answer 73

nope, cuz most of the time you're checking your answers :)
gimme a sec, I'll find an example...

Answer 74

Oh, ok.. if you say so.. phew! :)
Ok, I'll wait

Answer 75

http://openstudy.com/study#/updates/52b348bde4b03e81ff954681

Answer 76

OMG.. :O That is NOT cool!

Answer 77

indeed -.-

Answer 78

Hmm.. your too nice to have answered them >,< cheaters..

Answer 79

there's a lot of cheaters on this site -.-"

I'm thinking about signing up to try to become an ambassador on this site...

Answer 80

What is an ambassador?

And can you tell me the difference between a solid circle and an empty one? Does ≤ and < have anything to do with it?

http://static.k12.com/calms_media/media/212500_213000/212713/1/556fb09d1057b44d43dd6c45f65425352134d2b7/ALGTests_L2_S1_U9_Q9_B.gif

Answer 81

an ambassador are the people on this site that have the purple A next to their name, they get to welcome newcomers and have a chance to become a moderator :P

solid hole means would refer to the "or equal to" part
if it doesn't have that part then it would be an empty one :)

Answer 82

Oh, thats cool! How will you become one?

I get is, so empty = < or >
And solid = \[\le or \ge \]

Answer 83

http://blog.openstudy.com/2013/09/09/the-openstudy-ambassador-program/

and yep :)

Answer 84

bye and good luck :)

Answer 85

@jigglypuff314

Answer 86

hi :)

Answer 87

Hi, I'm back :) I was wondering if you can help me with drawing graphs?

Answer 88

sure :)

Answer 89

Thanks :)

These:

2y = –3x + 5
2x + 3y = 4


3x + 6y = 8
y = 2x – 8

I'm not soo good with graphs.. :(

Answer 90

well you could convert it into slope intercept form
then you know how to graph stuff when they're in slope intercept form right? :)

Answer 91

Hmm.. give me a min

Answer 92

I don't know.. :'(

Answer 93

2y = –3x + 5 -> y = -3/2 x + 5/2
2x + 3y = 4 -> y = -2/3 x + 4/3

Answer 94

Woah.. how did you get all that? O.o

Answer 95

2y = –3x + 5
divide both sides by 2
y = -3/2 x + 5/2

2x + 3y = 4
3y = -2x + 4
divide both sides by 3
y = -2/3 x + 4/3

Answer 96

Oh, I see. Now we go to the graphs?

Answer 97

yep :)