Question

Help me graphing please

Answer 1

-2x+y>=3

Answer 2

@mathmale

Answer 3

Someone please

Answer 4

Dan: Isolate y in -2x+y>=3 by adding 2x to both sides. Please type your result.

Answer 5

y=2x+3

Answer 6

y<=3x+3

Answer 7

the sign switch right?

Answer 8

Great, except that it's y "is equal to or greater than" 2x+3.
No sign switch here. Your y was already positive. That's what we want. We got rid of 2x on the left side and thus isolated y, right?

Answer 9

yes

Answer 10

OK. Next, we need to graph y=2x+3. Notice that I've omitted the > symbol for the present.

Are you readily able to graph y=2x+3, or do you need some review?

If you can graph it yourself, please go ahead.

Answer 11

we need to put this in y = mx + b form
-2x + y >= 3 --- add 2x to both sides
y >= 2x + 3
In y = mx + b form, the m is the slope and the b is the y intercept.
slope = 2
y intercept = (0,3)
To find the x intercept, sub in 0 for y
-2x + y = 3
-2x + 0 = 3
-2x = 3
x = -3/2 (x intercept is (-3/2,0) for graphing purposes, -3/2 = -1 1/2
so plot your intercepts (0,3) and (-3/2,0)

you can also start at the x intercept (-3/2,0) and since the slope is 2, go up 2 (because it is positive) and to the right 1, and up 2, and to the right 1, and you should cross the y axis at (0,3)

It will be a solid line because there is an equal sign. It will be shaded above the line because y is >= (greater then or equal)

Answer 12

Ok i wll do it

Answer 13

Done

Answer 14

@mathmale

Answer 15

Now?

Answer 16

Please @mathmale

Answer 17

Sorry for the delay, Daniel. Where are you now in the solution of this problem? Were you able to follow all of texaschik's instructions, and, if so, do you have the graph completed?

Answer 18

No, i didnt get it

Answer 19

I just have the Line in the graph

Answer 20

daniel, to be honest with you, I'm involved in helping another student at the moment, but I promise to get back to you. Perhaps you could take a break or consider how to solve the next problem on your list. C u shortly. MM

Answer 21

ok

Answer 22

We're graphing y=2x+3. Are you satisfied that you've graphed that correctly?

Answer 23

yes

Answer 24

Good. The original problem statement asks you to graph the inequality -2x+y>=3.
You already have a graph for -2x+y=3.
Now consider the inequality -2x+y>3.

Pick any point at random from your cartesian plane that is NOT on the line you've drawn.
Type it back to me in the form (x,y).

Answer 25

(1,1)

Answer 26

So you've chosen x=1 and y=1. Great. Would you please substitute those values into the inequality -2x+y>3 and determine whether or not the inequality is now true.

Answer 27

Here's what I meant: if x=1 and y=1, then -2x+y>3 becomes
-2(1)+(1)>3

and your task is to determine whether or not that inequality is true.

Answer 28

-1>=3
No

Answer 29

so it isnt true right

Answer 30

Dan, if your inequality is false, this is an indication that you need to shade the OTHER side of the graph. Do that, and you'll be done.

Or, if you'd like to udnerstand this process better, choose a point from the other side of the graph and test the inequality in the same way. If it is now true, that means that you've chosen a point from the "right" / "correct" side of the line to shade.

Answer 31

You've done nothing wrong. You found that the inequality wasn't true, which indicates that you need to shade the other side of the line. That's it.

Answer 32

Ok. Now i got it

Answer 33

I'm really happy for you. Thank you for sticking with this problem and with me all the way through.

Answer 34

Thanks to you