## anonymous 3 years ago Determine the value of f(-6), f(3/2), f(2c) and f(c+1), then simplify as much as possible Question : f(x) = 3x^2 - 4x

1. anonymous

2. anonymous

Well, in the first two, just take the appropriate number and plug it in where x is. Then simplify it down. For the third one (2c) replace x with 2c, then see what you get. Same for the fourth one. The first two are plug'n'chug, but if you need help with the second two I'll stick around.

3. anonymous

the second two, just plug it in to every x in the problem ?

4. anonymous

Mhm. So f(2c) would like$f(2c)=3 \times (2c)^{2}-4 \times (2c)$

5. anonymous

Ok let me try thanks!

6. anonymous

ummm question

7. anonymous

Yes?

8. anonymous

kinda dumb question but for the first one f(-6) i did -6=3(-6)^2-4(-6) -6=108+24 -6=132 then at this step do you add the 6 over or minus the 132 over ?? lol

9. anonymous

it usually easier if one size has a (x)

10. anonymous

Well, the left side is f(-6) not -6. So when you get to f(-6)=132, you are finished with that part.

11. anonymous

Since you've found the value in the range (132) that corresponds to the value of -6 in the domain.

12. anonymous

i see

13. anonymous

the second one i found is 3/4 hope its right

14. anonymous

the third one i got: f(2c) = 4c

15. anonymous

and do you divide the 2c over ?

16. anonymous

I also got 3/4

17. anonymous

cool :D

18. anonymous

Well, with these problems you only need to simplify the right side, don't worry about the left side at all. In the third and fourth ones your answer will be in terms of c though.

19. anonymous

so is my answer for the third one okay ?

20. anonymous

Well, no.$(2c)^{2}=4c^{2}$and there is nothing in there to cancel it, so you should have a c^2 term.

21. anonymous

how did you get 2c^2 on the left side ?

22. anonymous

isn't it 2c ?

23. anonymous

$f(2c)=3(2c)^{2}-4(2c)$and$(2c)^{2}=4c^{2}$so$f(2c)=3 \times 4c^{2}-4(2c)$

24. anonymous

oh so you can't multiply the term -4 with 2c ?

25. anonymous

You can, but I was leaving it for you to do. :P

26. anonymous

ohhhh lol

27. anonymous

at first i thought u can make (2c)^2 = 4c and just X 3 = 12c

28. anonymous

i was wrong :|

29. anonymous

Pretty close, just forgot the ^2 part of it. :P

30. anonymous

u mean 12c^2 ?

31. anonymous

Yep

32. anonymous

but why ? :O isn't it already been done on the 2c^2 ?why ^2 another

33. anonymous

@___@

34. anonymous

Well$(2c)^{2}$is the same thing as$2c \times 2c$Does that make it more clear?

35. anonymous

does that make 4c ?

36. anonymous

and 4c x 3 = 12c lol ?

37. anonymous

$2c \times 2c = 4c^{2}$

38. anonymous

ohhh lol =___=

39. anonymous

omg...my mind is somewhere else today....sorry

40. anonymous

Mine is too, don't worry.

41. anonymous

42. anonymous

so once i got f(2c) = 12c^2 - 8c then what can i do next?

43. anonymous

Well, at this point all of the same powers of c are together, so you're done.

44. anonymous

what do you mean by "same powers of c are together" ? :d

45. anonymous

Well, there's only one c^2 term and only one c term. You can't combine the c^2 and the c terms, so there is nothing left to do.

46. anonymous

i see

47. anonymous

the fourth one im stuck completely :D

48. anonymous

Well, what is$(c+1)^{2}$?

49. anonymous

(c+1)(c+1)

50. anonymous

So FOIL it out! :P

51. anonymous

ohh let see

52. anonymous

c^2+2c+1 and i think u can factor it more right ?

53. anonymous

Well, we don't want to factor it right now. So now$f(c+1)=3 \times (c^{2}+2c+1)-4 \times (c+1)$Can you finish it from there?

54. anonymous

kk hold on

55. anonymous

i think it is : f(c+1)=3c^2 + 2c -1

56. anonymous

Yep!

57. anonymous

awesome! lol

58. anonymous

so is that it ? o_0

59. anonymous

Yep

60. anonymous

cool! thanks Aylin

61. anonymous

You're welcome.

62. anonymous

your really good in math :D genius maybe?

63. anonymous

Not really, I just want to teach math.

64. anonymous

btw are you in college?

65. anonymous

oh ! so your a teacher :D

66. anonymous

wow! how lucky i am :D

67. anonymous

Not yet. I'm a senior at RPI.

68. anonymous

But next year I hope to be a teacher.

69. anonymous

70. anonymous

In May

71. anonymous

oh wow, almost there!

72. anonymous

how many years did you spend in RPI ?

73. anonymous

The end of this year will make three years.

74. anonymous

that's really quick wow

75. anonymous

is this it ? "Rensselaer Polytechnic Institute" ?

76. anonymous

Yeah. Not really very fast though; I spent two years at another school first.

77. anonymous

I see, still not bad. I had a friend who spends 3 years at community college and transfer

78. anonymous

what's the GPA for acceptance in RPI?

79. anonymous

It was a community college that I came from, actually. From another college or from high school?

80. anonymous

another college

81. anonymous

yeah, everybody is doing community college first now aday, cuz it's so much cheaper :D

82. anonymous

Minimum is 3.0 Higher is better of course, but they also like it if you've been taking mostly science and math courses (or engineering if that's your major choice) if possible.

83. anonymous

make sense.

84. anonymous

well thanks so much for talking with me Aylin. I gotta get to dinner now :D

85. anonymous

Like if you took a lot of math/science courses and made mostly Bs, it would look better than if you had made As taking mostly things like Art or Chorus or History

86. anonymous

Bye

87. anonymous

anything with science and math is better...and it's the subjects that im most terrible at. WOW..

88. anonymous

well bye for now :d

89. anonymous

Well, the other thing is that RPI is about $60000 a year right now, so... 90. anonymous your kidding me? no way 91. anonymous 92. anonymous so how much for 1 semester of full time? 93. anonymous omg wow... 94. anonymous About half, but it depends on what your dining plan is, where you live, ect. 95. anonymous omg so much debts...well but it's COLLEGE that we're talking about here so no suprise.. :| 96. anonymous one time I read that article about this college couples graduated with over 200k debts scared the hell out of me :| 97. anonymous I'm gonna have about$45K.

98. anonymous

did they tell you about the rate? or how much you have to pay back once your graduated ? I mean monthly?

99. anonymous

At some point probably. I don't remember what it is right now.

100. anonymous

oh i see, well i hope you can pay back all the debts without too much trouble :|

101. anonymous

I should be able to.

102. anonymous

Which year are you in?