## anonymous one year ago Algebra help please? Compare and contrast these four functions using complete sentences. Focus on teh slope and y-intercept first, and then on any additional properties of each function. I alread have some of it, but I need some help.

1. anonymous

Here are the four functions:

2. anonymous

3. anonymous

I already have that f(x) = 2x + 5 and it gives me j(x) = 2x - 5. I think g(x) = 4x - 8 and h(x) = 2x - 1 but I'm not sure of those two are correct.

4. anonymous

It's an essay question, not multiple choice

5. anonymous

idk

6. anonymous

@Nnesha Do you think you can help?

7. Nnesha

for h(x) line is increasing or decreasing ?

8. anonymous

decreasing

9. anonymous

It's starting at the five and going over 1 and down 2. I don't know how to write that though.

10. Nnesha

so what does it means ?

11. Nnesha

slope would be what ?

12. anonymous

1/2?

13. Nnesha

nope if line is decreasing then slope would be negative

14. anonymous

Oh yeah, so it'd be -1/2?

15. anonymous

yes

16. Nnesha

nope 2 is right slope is rise over run = 2/1 =2 it's decreasing so would be negative

17. anonymous

Oh okay. So the function would be h(x) = 5x - 2?

18. Nnesha

hmm y-intercept is a point where line intersect y-axis y=mx+b where m is slope b is y-intercept

19. anonymous

y = mx + b sooo h(x) = -2x + 5

20. Nnesha

yes right

21. anonymous

Okay, thank you. Now what about the g(x) function. Did I get that equation right?

22. Nnesha

nope slope and y-intercept both are wrong try again show ur work so i can find out the mistakes :=)

23. anonymous

Well I said it was g(x) = 4x - 8 because under the x column it is increasing by 4 and under the g(x) colume it is increasing by -8.

24. Nnesha

x isn't increasing by 4 would you add 4 with -2 to get 2 ?

25. anonymous

Yes... -2 + 4 = 2 then 2 + 4 is 6

26. anonymous

Even my calculator says that -2 + 4 is 2

27. Nnesha

hmm that's not a good way to find slope you should use slope formula

28. Nnesha

y-intercept isn't 8

29. anonymous

g(x) is increasing by -8 though. -1 - 8 = -9 and -9 - 8 = -17

30. Nnesha

that's not right slope isn't 4 use the slope formula $\huge\rm \frac{ y_2 -y_1 }{ x_2 -x_2 }$

31. Nnesha

wait a sec i see

32. anonymous

I don't have coordinates so I can't use that formula.

33. Nnesha

that's the difference of y's and x's y's =-8 x's = 4

34. Nnesha

so replace y_2 -y_1 = -8 and x_2 - x_1 =4 that would give you slope

35. anonymous

I don't understand what you're telling me to do.

36. Nnesha

|dw:1441982763195:dw| coordinates

37. Nnesha

you can use the table to find slope (-2 ,-1)(2,-9)(6,-17) are coordinates

38. Nnesha

slope formula is $\huge\rm \frac{ difference~of~y }{ difference~of~x }=\frac{ y_2-y_1 }{ x_2-x_1 }$

39. anonymous

Oh! Okay so... y2 - y1 / x2 - 1 -9 - (-1) / 2 - (-2) = -8 / 4 simplified would be... -2

40. anonymous

So -2 is my slope?

41. Nnesha

and you said x is increasing by 4 and y increasing by -8 that's difference between y and x's $\huge\rm \frac{ difference~of~y }{ difference~of~x }=\frac{ y_2-y_1 }{ x_2-x_1 }=\frac{-8}{4}$

42. Nnesha

yes right

43. anonymous

Now how do I figure out my y-inercept? Do I just use -8? So my function would be: g(x) = -2x - 8

44. Nnesha

nope use on of the order pair (x,y) plug that into the equation y =-2x+b

45. Nnesha

one*

46. anonymous

So my function is g(x) = -2x - 5, right?

47. Nnesha

looks good

48. anonymous

Omg, thank you so much!!! You are the best

49. Nnesha

yw good work!

50. anonymous

Do you mind checking a question for me? I already did it but I'm not sure if it's right.