## toxicsugar22 5 years ago Find the first three terms of the product in acending powers. (1-2x^2-x^4)(4+x^2-2x^4)

1. anonymous

well, why don't you multiply the two polynomials and post what you got?

2. toxicsugar22

ok

3. toxicsugar22

i got 4-x^2-2x^4-8x^4x^6-4x^4-x^6-2x^8 is that right and if it isnt caould you please correct me

4. anonymous

okay so you got that. why don't you add up the like terms and post it here. for example, -2x^4 - 4x^4 = -6x^4

5. anonymous

there should be a plus of minus sign between 8x^4 and x^6 in the polynomial you posted

6. toxicsugar22

so my answer is not right

7. toxicsugar22

ohh i see there is a minus between 8x^4 and x^6

8. toxicsugar22

4-x^2-2x^4-8x^4-x^6-4x^4-x^6-2x^8

9. anonymous

okay, but you have to add up the like terms. you see, a^2 +3 a^2 = 4a^2. similarly -2x^4 - 8x^4 = -10x^4

10. anonymous

and so on. so group all the terms together and write down your expression

11. toxicsugar22

i dont know but i got 4-x^2-14x^4-2x^6-2x^8

12. toxicsugar22

is that right

13. anonymous

yes, that seems to be right. all you have to do now is see what the first three terms are in ascending order of powers.

14. toxicsugar22

is it 4-x^2-14x^4

15. anonymous

yes.

16. toxicsugar22

ok thanks you

17. toxicsugar22

cana you help me with on more promblem

18. anonymous

although you should say, the first three terms are 4, -x^2 and -14x^4

19. anonymous

you are welcome. post your other problem and we will see how to solve it.

20. toxicsugar22

A large wooden box is 3 feet longer than it is wide, and its height is 2 feet shorter than its width. a. If the width of the box is w, write expressions for its lenghth and its height. b. write a plynomial for the volume of the box. c. Write a polynomial for the surface area of the box

21. toxicsugar22

do u get it or no

22. toxicsugar22

ok srry not that one

23. anonymous

yes, i got it. do you want the answer or not?

24. toxicsugar22

yes

25. toxicsugar22

thanks

26. anonymous

okay it says the box is 3 feet longer than its width. so length = ?

27. toxicsugar22

i dont know can u show me the firt time please

28. toxicsugar22

29. anonymous

if width is w, length = w + 3feet.

30. anonymous

so if height is 2 feet less than width, height = ?

31. toxicsugar22

2-w

32. toxicsugar22

or w-2

33. anonymous

yes, w -2 is correct. so width is w, length is w+3 and height is w-2

34. anonymous

what is the volume and surface area then?

35. toxicsugar22

im not sure surface area is( w-2)(w+3)

36. toxicsugar22

can u help me

37. anonymous

what is the volume of a cuboid?

38. anonymous

just tell me the general formula.

39. toxicsugar22

ok the surface formula

40. anonymous
41. anonymous
42. toxicsugar22

s=2lh+2wh+2lw

43. toxicsugar22

is that it

44. anonymous

yes. so express the surface area in terms of the height width and length of your cube.

45. toxicsugar22

so do i plug in the 3 and 2 for the height and the width

46. anonymous

your height is w -2 and length is w+3 and width is w. so plug those values.

47. toxicsugar22

so s=2(w+3)(w-2)+2(w)(w-2)+2(w+3)(w)

48. toxicsugar22

is it right

49. anonymous

yes

50. toxicsugar22

now do i distrubuite

51. anonymous

yes, you can do that

52. toxicsugar22

how do i muliply 2(w+3)(w-2)

53. toxicsugar22

can you just show me

54. anonymous
55. toxicsugar22

ok i got 6w^2+4w-12 is that right

56. toxicsugar22

is it right

57. anonymous

no

58. toxicsugar22

than can u help me

59. toxicsugar22

60. anonymous

i gave you the link, did you use it?

61. toxicsugar22

yes ill do it again

62. anonymous

okay.

63. toxicsugar22

igot the same thing

64. toxicsugar22

unless im doing something wrong

65. toxicsugar22

r u there

66. anonymous

yes, $2(w+3)(w-2)=2(w \times w +3 \times w -2 \times w -2 \times 3)$

67. anonymous

$= 2(w ^{2}+w-6)=2w ^{2}+2w-12$

68. toxicsugar22

is that it

69. toxicsugar22

is that the anwer to that question

70. anonymous

no, that is the multiplication of 2(w+3)(w-2) the surface area is 2 lw+2lh+2hw and the volume is lwh

71. toxicsugar22

ok can u help me step by step please

72. toxicsugar22

im so lost

73. toxicsugar22

can u help

74. anonymous

what do you need help with? I already explained everything to you.

75. toxicsugar22

76. toxicsugar22

please like how do u solve 2(w+3)(w-2)+2(w)(w-2)+2(w+3)(w)

77. anonymous

2w(w-2) = 2w^2-4w 2w(w+3) = 2w^2+6w. 2(w+3)(w-2) = 2w^2 +2w-12 add all three and post what you get.

78. toxicsugar22

6w^4w-12 is that right

79. toxicsugar22

is it

80. toxicsugar22

81. toxicsugar22

r u there

82. anonymous

yes that is right. that is the surface area.

83. toxicsugar22

ok and the volume of the box

84. toxicsugar22

the surface area of the the box is 6w^6+4w-12

85. anonymous

how did you get 6w^6 term in there?

86. toxicsugar22

i dk

87. anonymous

can you add the three terms like I said and post it here properly?

88. toxicsugar22

i did

89. anonymous

2w(w-2) = 2w^2-4w 2w(w+3) = 2w^2+6w. 2(w+3)(w-2) = 2w^2 +2w-12 add all three and post what you get

90. toxicsugar22

that is what i got but i can doit again

91. anonymous

so how did you get a w^6 term there if you added them properly?

92. toxicsugar22

2w^2-4w 2w^2+6w. 2w^2 +2w-1=6w^6+4w-12

93. anonymous

okay, you added 2w^2+2w^2+2w^2 and got 6w^6?

94. toxicsugar22

95. anonymous

you added -4w+6w+2w and got 4w correct?

96. anonymous

then how did you add 2w^2+2w^2+2w^2 and get 6w^6? according to your logic, -4w+6w+2w should be 4w^3 isn't it?

97. toxicsugar22

98. anonymous

no, I can't. I don't think you understood what I am trying to say to you. if you add 2 oranges to 2 oranges, how many oranges do you get?

99. toxicsugar22

4

100. anonymous

you get 4 what?

101. toxicsugar22

oranges

102. anonymous

okay so if you add two w squares to two w squares, how many w squares do you get?

103. toxicsugar22

4 w

104. anonymous

you get 4 w squares. correct? so if you add 2 w squares to two w squares to two w squares, how many w squares do you get?

105. toxicsugar22

6w

106. anonymous

okay, so what is 2w^2+2w^2+2w^2?

107. toxicsugar22

6w

108. anonymous

how is it 6w? you are saying that if you add 2 oranges to 2 oranges to 2 oranges you get 6 apples. how does that make any sense?

109. toxicsugar22

can u just show me

110. anonymous

okay. 2 w^2 +2w^2+2w^2 = 6 w^2, not 6w^6

111. anonymous

do you understand?

112. toxicsugar22

ok thanks

113. anonymous

w^2 is the same as w times w.

114. toxicsugar22

i understand

115. toxicsugar22

can u help me with the volume now

116. anonymous

no, I think you can do that on your own. I will give you hint. volume is length times width times height. length is w+3, width is w and height is w-2 multiply all three.