2x-5y=8, 5y<2-8, 5y>2x-8, 2^-5=8: solve to put in graph

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therese478

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I have been trying to solve these to problem in order to graph and I do not know what to do at all.
2x-5y=8
5y<2-8 or 5y>2x-8 I have to put these in agraph program and do not understand how to solve them to put in a graph. I thing the first one I do 2^-5=8
 
Have you made one or more typos? Please, very carefully compare what you have typed with the actual problem and make corrections so that we know what the problem is. Then, if you can, show or tell us what you have done so far.
 
I am trying to create a graph that show a breakeven point for the company.
first a linear equation of the form 2x-5=8.
linear inequality in the form 5y<2x-8 0r 5y>2x-8.
I have to solve the equations first in order to put the problems in a gragh. In using a gragh programthe
linear I tried this Fx=2^-5=8 but I will not take the =8 part.
For the inequality I do not understand how to solve to put in the graph program.
 
You need to solve the equation for y to see the expression to graph.

2x - 5y = 8

Subtract 2x from both sides.

-5y = 8 - 2x

Multiply both sides by -1/5

y = -(8/5) + (2/5)x

You can enter this into the calculator as Y= 2x/5 - 8/5

 
When graphing this inequality 5y>2x-8 how do I solve for x, and y. my linear was.
Do i cancel out by adding or subtracting on both sides or do I need to add one side then subtract the second side. when canceling out. to sovle.
 
when I graph linear equation 2x/5-8/5 and inquality 5y>2x-8 how do I get the exact breakeven point on the graph how do I go about solving to find the problems in order to pinpoint it on a graph.

Here is what I did so far. solved my linear 2x-5y=8, -5y=8-2x,multiply both sides by 1/5, y=-(8/5)+(2/5)x.
I put that in the graph.

The inequality 5y>2x-8 Variable y Result y>2x/5y=8 solve 2x-5y=8, Valiables x,y , Result x=5y/5+4
I put that in a graph as Insert Relation 5y>2x-8.

Now I need to get the breakeven point together where they met on the graph. It says to be exact. Thats is what I do not know how to do.

Thank you.
 
5y>2x-8

I assume you are graphing this inequality on the rectangular coordinate system. Temporarily change the ">" symbol to an "=" sign and graph that line. The line is dashed if the inequality is "<" or ">" and solid if the inequality is "<" or ">". Then determine which half-plane satisfies the original inequality and shade that side in.
 
Hello Therese:

I'm motivated to help you, but I regret that I feel a need to spend the little time that I have before leaving for dinner by posting the following instead of asking you the questions that I would need to ask in order to decipher exactly what it is that you are trying to accomplish.

1) This is a continuation of the thread titled, "Problem solving algebra", which you started on the Beginning Algebra board. Please post replies to a discussion at the end of the original discussion; please do not start new threads to continue a discussion that is taking place somewhere else. Otherwise, people need to jump back and forth between the two threads to see the entire discussion.

I am far too lazy to do that. :lol:

2) You are a very sloppy typist.

So far, you have typed each of the following to mean exactly the same equation:

2x-5y=8
2^-5=8
2x-5=8
2x/5-8/5 ? this one does not even contain an = sign

You've been just as sloppy typing the inequalities.

I am not too lazy to guess what you are trying to say. I just don't have any more time at this moment.

Your goal is also not clear to me. You imply a problem where the solution is found graphically by looking for some type of intersection point. Yet, your use of phrases like "break point" could imply something else entirely.

When I get back from dinner, I will check back to see if anybody else has found any motivation to start the process of asking you the specific questions that we need to ask so that we understand what it is that you're trying to accomplish.

If nobody has, then I'll be eager to continue to try to help you at that point.

Cheers,

~ Mark :)

PS: Please try out the [Preview] button, right next to the [Submit] button. You can see (before you submit) what the post will look like on the board. This makes it easy to proofread.

 
I was trying to find out the break even point for a company in supply and demand. I've done my graphs.
Linear was 2x-5y=8.
Inequality was 5y>2x-8.
My third graph was putting the two graphs together..
But now I need to make the same comparisons with financial numbers.
I used 2x+ 20 as my cost. y=cost
I used 4x+16 as my revnue. x=revnue
where does the graph show a break even point is what I am trying to figure out.
 

I note that this conversation is now taking place in three different locations ...

therese478 said:
I've done my graphs.
Linear was 2x-5y=8.
Inequality was 5y>2x-8.
My third graph was putting the two graphs together.
Click to expand...

The equation that defines the boundary of the shaded region on your inequality is the same equation for the linear graph. Are you sure that both graphs are supposed to show the same line?

therese478 said:
I was trying to find out the break even point for a company in supply and demand ... I used 2x+ 20 as my cost. y=cost
I used 4x+16 as my revnue. x=revnue ... where does the graph show a break even point is what I am trying to figure out.
Click to expand...

I understand what the break-even point is with respect to costs and revenue, but I would need more information to be able to think about a break-even point with respect to supply and demand. You did not define x. What does x represent? Does x stand for a production number for something that this company manufactures? I'll guess that does.

Actually, you do state that x = revenue, but I don't think this makes sense. Otherwise, if x is the revenue and the cost is calculated by 2x+20, then that equation says that the costs for this business are 20 dollar units more than twice their revenue. That's not a very good business model.

Cost is an amount of money. Revenue is also a dollar figure. A company has to spend money to make money. If they manufacture too many products (i.e., x is too high), then the cost will be GREATER than the revenue, and they lose money. If they manufacture less than this number of products, then the cost will be LESS than the revenue, and they make money.

The break-even point is the value for x that makes cost = revenue. In other words, to "break even" means that you only bring in as much money as you owe; you don't lose any money, but you don't make any either.

The linear relationship between the number of products made (x) and the cost to make those products (C) is expressed by:

C = 2x + 20

The linear relationship between the number of products made(x) and the revenue brought in by selling them (R) is expressed by:

R = 4x + 16

If you graph both of these lines on the same coordinate system, then the break-even POINT is where the two lines INTERSECT. The value of x at that point makes both the cost and the revenue equal (the same amount of money).

I do not know how this value of x relates to your first two graphs (the two with the same line) because I do not know what those graphs represent.

Can you graph both of the lines y = 2x + 20 and y = 4x + 16 to find out where they intersect?

If you are not told to find the break-even point with respect to cost and revenue BY GRAPHING, then there are other ways to find the x-coordinate and y-coordinate of the intersection POINT. Namely, by solving both the cost and the revenue equation simultaneously using algebra to find x and y.

If this does not help, then maybe I've guessed totally wrong. I will need you to type the entire problem that you were given, along with all of the instructions.

Cheers,

~ Mark
 
mmm4444bot said:
I note that this conversation is now taking place in three different locations ...
Click to expand...
Various threads merged.
 
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