Question

How do I solve these systems of equations x + y = 3 and x - y = 1 by graphing?

Answer 1

well first you're going to want to get them in standard form.

Answer 2

y=

Answer 3

Oh... Y = mx + b? or just Y =?

Answer 4

y=mx + b. Silly keyboard :D

Answer 5

Once you get them into standard form, you'll be right next to graphing them (: I'll help with that too.

Answer 6

IS y = x + 3 correct for the first one?

Answer 7

For slope-intercept form (y = mx + b), you basically isolate the y.

Answer 8

"IS y = x + 3 correct for the first one?"

Close, you were suppose to subtract both sides by x.

Answer 9

There I go again mixing up names again, thank you Micah. ><"

Answer 10

You would subtract x from both sides, canceling the x on one side, but that negative should stick by aswell.

Answer 11

Uhh.... y - x = 3?

Answer 12

x + y = 3
-x -x

Answer 13

So here, your x on the left should cancel and will end up on the right as a negative.

Answer 14

solve for y on both equations and you will get
y =3-x, intercept at (0,3) with slope of -1
and
y= x-1, intercept at (0,-1), with slope positive 1

Answer 15

Well, that did the work for him xD No good. ><"""

Answer 16

^ Agreed, But don't worry I'm still working on understanding the process and not just slapping down the answers

Answer 17

sometimes you learn faster knowing the answers first so you know what you need to do to get that answer

Answer 18

Wait... Jayz said it's y = x - 1, I got -y = 1 - x

Answer 19

all you have to do there is divide the equation by negative one, and you'll get that EXACT answer, you're on the right track and just a step away.

Answer 20

Oh dividing it gives me -1 and makes the x positive, so i switch the order to y = x - 1 right?

Answer 21

Yes! There you go (:

Answer 22

Woo, thanks!

Answer 23

Now how do I graph? :s

Answer 24

Alright, you see that -1 there? That's going to be one of the intercepts. Do you know what intercepts are?

Answer 25

Yes, so the -1 is the y intercept one right? so I put the point on -1 in the y line?

Answer 26

Yeah, exactly!

Answer 27

Once you have that there you're going to need to know it's slope, so you can add more 'points' and graph a line for that equation.

Answer 28

Slope is 1 right? single x = 1?

Answer 29

Yeah, the slope is positive and going up one. You're on the right track!

Answer 30

Do you have an idea of how that would look?

Answer 31

one up and one right or just one up?

Answer 32

Ah, you're going to want to go one up and one right (:

Answer 33

Oh yeah because 1/1 rise over run.

Answer 34

and then I work on graphing y = 3 - x right?

Answer 35

Yeah, exactly. I'll graph it for you, too. Just so you have an example. We still have the other one to do.

Answer 36

Yeah, the same way the other one was done.

Answer 37

Yeah mine looks like that

Answer 38

Great, awesome. Good job!

Answer 39

for y = 3 - x... 3 is the y intercept and 3 is the slope right?

Answer 40

errr x is the slope*

Answer 41

the y intercept is the 3, and your slope is the -x.

Answer 42

so the points on this one are (0,3) and (-1, 2)?

Answer 43

y=mx+b

m is your slope
b is your intercept

In this case your m is -1x (: for future reference

Answer 44

This one's slope isn't -1/2 though

Answer 45

your -x is your slope and that's just like the last equation's slope x - but it's negative instead of positive.

Answer 46

-1/1 right?

Answer 47

Yeah!

Answer 48

so the points are (0,3) (1,2)?

Answer 49

exactly that. ^^

Answer 50

You should have something like this.

Answer 51

Exactly that, thanks a lot for helping me out with this question. Out of curiosity what do you use to make those graphs?

Answer 52

MS paint with a background of a graph - nothing fancy at all. ^^ I wish I could tell you I used some kind of graphing program :P

Answer 53

Great job, glad you were able to figure it out. (:

Answer 54

Alright, seriously though thanks for the help, I was about to give up on this.

Answer 55

O.o I'm glad you didn't
Good luck with math!