Question

how do i figure this inequality:
3x-7y>21

Answer 1

Are you solving for y?

Answer 2

i really dont know i think im supposed to find out if the left side of the inequality is greater than the right side

Answer 3

Well it depends on what x and y is. However based on the looks of the problem (and my experience with people who have the same questions), they are probably wanting you to solve for y.

Answer 4

idk my math teacher told me to use the coordinates (0,0)

Answer 5

That would change things slightly (you probably should have wrote that with the problem). If you are using the coordinates (0,0), then you will substitute 0 for x and 0 for y. Then you will have 3(0)-7(0)=0.
However, is 0 greater than 21?

Answer 6

no it isnt but problem is my graph only goes to ten

Answer 7

Are you using a graphing calculator? If so which one?

Answer 8

im bnot its a take home test and thats as long as they made the graph i was wondering if there was a way to simplify it

Answer 9

Solve for y. Then you can subtract 3x from both sides of the inequality, so -7y>21-3x.
Then divide both sides by -7; however, do you know what happens to the inequality when you divide by a negative sign?

Answer 10

ummmm is it that -7y gets divided by 21-3x which would make the inequality y>-3-(-3/-7) right?

Answer 11

Umm not quite.

What I meant to say is, when you divide by a negative sign (-7 in your case), the inequality sign ">" will turn the opposite direction ("<"). You can flip the direction only if you divide by a negative (this is a good thing to know).

So your inequality should be y< (21-3x)/(-7)

Answer 12

oh ok i see it now thankyou

Answer 13

Is there any step that did not make sense?

Answer 14

no my math teacher goes to fast in class so i dont get most of it but you made it very clear to me now thankyou

Answer 15

You're welcome!

Answer 16

ok thats all