## Shido88 2 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. Shido88

2. Aylin

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. Shido88

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

4. Aylin

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

5. Shido88

Ok let me try thanks!

6. Shido88

ummm question

7. Aylin

Yes?

8. Shido88

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. Shido88

it usually easier if one size has a (x)

10. Aylin

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

11. Aylin

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

12. Shido88

i see

13. Shido88

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

14. Shido88

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

15. Shido88

and do you divide the 2c over ?

16. Aylin

I also got 3/4

17. Shido88

cool :D

18. Aylin

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. Shido88

so is my answer for the third one okay ?

20. Aylin

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

21. Shido88

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

22. Shido88

isn't it 2c ?

23. Aylin

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

24. Shido88

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

25. Aylin

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

26. Shido88

ohhhh lol

27. Shido88

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

28. Shido88

i was wrong :|

29. Aylin

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

30. Shido88

u mean 12c^2 ?

31. Aylin

Yep

32. Shido88

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

33. Shido88

@___@

34. Aylin

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

35. Shido88

does that make 4c ?

36. Shido88

and 4c x 3 = 12c lol ?

37. Aylin

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

38. Shido88

ohhh lol =___=

39. Shido88

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

40. Aylin

Mine is too, don't worry.

41. Shido88

42. Shido88

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

43. Aylin

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

44. Shido88

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

45. Aylin

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. Shido88

i see

47. Shido88

the fourth one im stuck completely :D

48. Aylin

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

49. Shido88

(c+1)(c+1)

50. Aylin

So FOIL it out! :P

51. Shido88

ohh let see

52. Shido88

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

53. Aylin

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. Shido88

kk hold on

55. Shido88

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

56. Aylin

Yep!

57. Shido88

awesome! lol

58. Shido88

so is that it ? o_0

59. Aylin

Yep

60. Shido88

cool! thanks Aylin

61. Aylin

You're welcome.

62. Shido88

your really good in math :D genius maybe?

63. Aylin

Not really, I just want to teach math.

64. Shido88

btw are you in college?

65. Shido88

oh ! so your a teacher :D

66. Shido88

wow! how lucky i am :D

67. Aylin

Not yet. I'm a senior at RPI.

68. Aylin

But next year I hope to be a teacher.

69. Shido88

70. Aylin

In May

71. Shido88

oh wow, almost there!

72. Shido88

how many years did you spend in RPI ?

73. Aylin

The end of this year will make three years.

74. Shido88

that's really quick wow

75. Shido88

is this it ? "Rensselaer Polytechnic Institute" ?

76. Aylin

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

77. Shido88

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

78. Shido88

what's the GPA for acceptance in RPI?

79. Aylin

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

80. Shido88

another college

81. Shido88

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

82. Aylin

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. Shido88

make sense.

84. Shido88

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

85. Aylin

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. Aylin

Bye

87. Shido88

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

88. Shido88

well bye for now :d

89. Aylin

Well, the other thing is that RPI is about $60000 a year right now, so... 90. Shido88 your kidding me? no way 91. Aylin 92. Shido88 so how much for 1 semester of full time? 93. Shido88 omg wow... 94. Aylin About half, but it depends on what your dining plan is, where you live, ect. 95. Shido88 omg so much debts...well but it's COLLEGE that we're talking about here so no suprise.. :| 96. Shido88 one time I read that article about this college couples graduated with over 200k debts scared the hell out of me :| 97. Aylin I'm gonna have about$45K.

98. Shido88

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

99. Aylin

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

100. Shido88

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

101. Aylin

I should be able to.

102. Aylin

Which year are you in?