## anonymous one year ago Anybody willing to help me with three easy questions please! I will fan and medal and love you forever <3

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1. anonymous

If h(x) = 4x − 8 and j(x) = −x, solve h[j(3)] and select the correct answer below. A. −36 B. −20 C. 1 D. 4

2. anonymous

a) what is $$j(3)$$?

3. anonymous

J is -x and 3 is just 3.... wait are u asking me or are you confused? :)

4. jim_thompson5910

satellite73 knows the answer s/he is asking you to see if you know it

5. anonymous

$j(x)=-x$ so $j(\spadesuit)=-\spadesuit$ and $j(\xi)=-\xi$ so what is $j(3)$?

6. anonymous

Oh ok... Yes so I did 4x-8[-x(3)] but i keep getting 28

7. anonymous

umm... -3?

8. jim_thompson5910

j(3) is -3, yes

9. anonymous

ok thanks

10. anonymous

whew b) what is $$h(-3)$$?

11. jim_thompson5910

notice how satellite73 replaced the "j(3)" with "-3" going from h[ j(3) ] to h(-3) this only works because j(3) = -3

12. anonymous

4x+24?

13. jim_thompson5910

replace every x in h(x) = 4x − 8 with -3

14. anonymous

oh ok so 4(-3) or -12 -8?

15. anonymous

$h(\diamondsuit)=4\times\diamondsuit-8$$h(\Phi)=4\times \Phi -8$$h(-3)+?$

16. jim_thompson5910

yeah just compute -12-8

17. anonymous

-20

18. jim_thompson5910

correct

19. anonymous

omg tysm!!

20. anonymous

I need help with 2 more... please

21. jim_thompson5910

22. anonymous

Ray is purchasing a laptop that is on sale for 25% off. He knows the function that represents the sale price of his laptop is c(p) = 0.75p, where p is the original price of the laptop. He also knows he has to pay 8% sale's tax on the laptop. The price of the laptop with tax is f(c) = 1.08c, where c is the sale price of the laptop. Determine the composite function that can be used to calculate the final price of Ray's laptop by solving for f[c(p)]. A. f[c(p)] = 1.83p B. f[c(p)] = 1.83cp C. f[c(p)] = 0.81p D. f[c(p)] = 0.81cp

23. jim_thompson5910

$\Large f(c) = 1.08c$ $\Large f(\color{red}{c}) = 1.08\color{red}{c}$ $\Large f(\color{red}{c}) = 1.08(\color{red}{c})$ $\Large f(\color{red}{c(p)}) = 1.08(\color{red}{c(p)})$ $\Large f(\color{red}{c(p)}) = ??$

24. anonymous

um...

25. jim_thompson5910

$\Large f(c) = 1.08c$ $\Large f(\color{red}{c}) = 1.08\color{red}{c}$ $\Large f(\color{red}{c}) = 1.08(\color{red}{c})$ $\Large f(\color{red}{c(p)}) = 1.08(\color{red}{c(p)})$ $\Large f(\color{red}{c(p)}) = 1.08(\color{red}{0.75p})$ $\Large f(\color{red}{c(p)}) = ??$ In the second to the last step, I replaced c(p) with 0.75p because c(p) = 0.75p

26. anonymous

0.81

27. jim_thompson5910

0.81p

28. jim_thompson5910

don't lose the p

29. jim_thompson5910

the c or c(p) goes away because it is replaced by 0.75p

30. anonymous

oh ok got it so c right

31. jim_thompson5910

yes

32. anonymous

The following table shows the length and width of two rectangles: Length Width Rectangle A 2x + 8 x − 1 Rectangle B 3x + 5 2x − 2 Which expression is the result of the perimeter of rectangle B minus the perimeter of rectangle A? A. 2x − 4 B. 8x + 10 C. 16x + 20 D. 4x − 8

33. anonymous

Thank you! Last question

34. jim_thompson5910

hint: Perimeter = 2*(Length + Width)

35. anonymous

ok so, 2*(2x+8)+(x-1) for the first one right?

36. jim_thompson5910

2*[ (2x+8)+(x-1) ] actually

37. anonymous

oh ok now what? when i simplify it i get 5x+15

38. jim_thompson5910

you should get 2*(3x+7) = ???

39. anonymous

ohh i see! ok so 6x+14?

40. jim_thompson5910

yes, that is the perimeter of rect A

41. jim_thompson5910

find the perimeter of rect B

42. anonymous

so for rectangle B would be 2*[ (3x+5)+(2x-2) ]

43. jim_thompson5910

yes

44. jim_thompson5910

I'll be right back

45. anonymous

ok

46. anonymous

is the answer 10x+6

47. jim_thompson5910

perimeter of rect A = 6x+14 perimeter of rect B = 10x+6

48. jim_thompson5910

subtract the two perimeters

49. anonymous

Well the directions say "perimeter of rectangle B minus the perimeter of rectangle A" but when i do that i get 4x+8 which is none of the options

50. jim_thompson5910

10x - 6x = 4x ... correct 6 - 14 = 8 ... incorrect

51. anonymous

Now I'm confused

52. jim_thompson5910

B - A = (10x+6) - (6x+14) = 10x + 6 - 6x - 14 = ??

53. anonymous

i got 4x+20

54. anonymous

Did you mean to put 10x + 6 - 6x + 14 = ?

55. jim_thompson5910

no the negative distributes through

56. jim_thompson5910

- (6x+14) = -6x-14

57. anonymous

oh ok so it would be the last one right?

58. jim_thompson5910

yeah 4x-8

59. anonymous

Thank you so much!!!!!!!!

60. jim_thompson5910

no problem

61. denisaboichuk

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