## jennyrlz one year ago Hey i need some algebra help :)

1. jennyrlz

so a friend of mine is asking for help but i don't really remember much of my algebra days :/

2. whpalmer4

so, what's the question?

3. jennyrlz

ok so first he was asked to draw a flag one sec let me draw it

4. jennyrlz

|dw:1433290028954:dw|

5. jennyrlz

|dw:1433290054568:dw|

6. jennyrlz

ok so lets get to the problem

7. jennyrlz

he os asked to show these points in y=mx+b and in standard form

8. jennyrlz

but if we already have all the x y's what do i do ; ;

9. jennyrlz

|dw:1433290221695:dw|

10. whpalmer4

maybe he's supposed to write equations for those lines that make up the diagram?

11. jennyrlz

hmm how would i go about doing this? he isnt really that familiar with the material :/

12. whpalmer4

Well, the vertical and horizontal lines are pretty easy. For example, the bottom line is a horizontal line that passes through (-5,-3) and (5,-3). We know the slope is 0, so it is just \[y=k\] for some value of \(k\), right? Doesn't matter what value of \(x\), \(y\) is always -3 for that line.

13. whpalmer4

Similarly, any vertical lines are just \[x=k\]for some value of \(k\), because all the \(x\) values are the same, and only the \(y\) value changes.

14. jennyrlz

1. draw the flag out in graphing paper, graph must include coordinates and labled increments plot each point at the end of each line segment on the flag for each line creat a table with four points write an equation in slope intercept and standard and list the domain and range

15. jennyrlz

those are the instructions

16. whpalmer4

Now, the "slanted" lines are probably what the problem author is interested in...there we know two points the line passes through, and from that, we can determine the equation of the line.

17. whpalmer4

okay, yeah, looks like what I guessed. Let's take that line from \((-5,-3)\) to \((0,0)\) as an example. The domain is going to be -5 to 0, inclusive; those are the values that \(x\) is allowed to take. \[-5\le x\le 0\]is another way you could write that. The range is the range of values \(y\) can have over the domain. At the minimum, \(y=-3\) and at the maximum, \(y = 0\), so we could write the range as \[-3\le y \le 0\] Any question about that?

18. jennyrlz

umm

19. jennyrlz

let me show you what i just did

20. jennyrlz

ahh |dw:1433290930006:dw|

21. jennyrlz

correct?

22. jennyrlz

and i still have trouble with domain and range

23. whpalmer4

yes, put 4 points in that table, different values of x, all the same value of y, and you have your table. Now domain is the set of allowed values of x (the independent variable), and range is the set of resulting values of y (the dependent variable). For this line segment, how would you describe the allowed values of x?

24. jennyrlz

hmm you lost me xD. but the allowed values reffer to the x then wouldnt they be -5 to 5 because thisline goes from -5 to 5?

25. whpalmer4

exactly. "domain" is just a fancy term to confuse you :-)

26. jennyrlz

xD

27. jennyrlz

and for range?

28. whpalmer4

isn't there only one possible y value for this line?

29. jennyrlz

what do you mean?

30. jennyrlz

i think i just made sense of it, the range would be 5 xD

31. jennyrlz

correct?

32. whpalmer4

no, the range is 3, isn't it? isn't y = 3 for all values of x for that line?

33. jennyrlz

oh yea i was refering to his table xD

34. jennyrlz

i made my own so i can help him xD

35. jennyrlz

Thank you SOOOOOOOOOO much.

36. whpalmer4