## andriod09 Group Title Algebra II question, a fraction on top of a fraction, please help me! one year ago one year ago

1. cpattison Group Title

a fraction on top of a fraction can be rewritten as say (2/3)/(3/4) then you can flip the second one because to divide you multiply by the reciprocal (2/3)*(4/3) then you multiply across the fractions (2*4)/(3*3).

2. andriod09 Group Title

$\huge\frac{\frac{30x^2+27x+6}{9x^2-49}}{\frac{30x+15}{30x-70}}$ That is the fraction.

3. andriod09 Group Title

@cpattison

4. andriod09 Group Title

@ganeshie8 @Hero

5. cpattison Group Title

oh okay

6. cpattison Group Title

one second!

7. Hero Group Title

Put a divide sign between both of them, then put them next to each other. You'll know what to do then.

8. Hero Group Title

$\huge\frac{30x^2+27x+6}{9x^2-49} \div \frac{30x+15}{30x-70}$

9. cpattison Group Title

((30x2+27x+6)/(9x2−49))/((30x+15)/(30x−70)) is where we start. then you can flip the bottom half and multiply ((30x2+27x+6)/(9x2−49))*((30x−70)/(30x+15)) then you just multiply though ((30x2+27x+6)*(30x−70))/((9x2−49)*(30x+15))

10. cpattison Group Title

yeah so flip that second fraction

11. cpattison Group Title

i really have to learn how to use the equation bar

12. andriod09 Group Title

@cpattison you should use the \$LaTeX$ by using the $\$ minus the \ in the middle.

13. cpattison Group Title

agreed

14. Hero Group Title

I just copied and pasted what @andriod09 wrote with a few minor changes :P

15. andriod09 Group Title

$\huge\text i-know-how-to-use-LaTeX$

16. Hero Group Title

Not as good as me :P

17. andriod09 Group Title

the answer isn't supposed to be like that. it is supposed to be on top of each other though. thats what it says. the answer it: $\frac{2(5x+2)}{(x-7)}$

18. Hero Group Title

You failed to execute the proper steps. That's why you didn't get it right

19. Hero Group Title

Did you flip the second fraction?

20. andriod09 Group Title

no. i don't know how to solve it like that, you have to factor it out is what the book says, but i don't get it.

21. Hero Group Title

If you had $\frac{3}{6} \div \frac{3}{9}$ you would have no clue what to do?

22. andriod09 Group Title

thats simple: $\frac{3}{6}\div\frac{3}{9}=\frac{1.5}{1}$

23. andriod09 Group Title

$:{$

24. Hero Group Title

actually, you have it but you failed to execuate the reciprocal rule

25. andriod09 Group Title

$:[$

26. Hero Group Title

$\frac{3}{6}\div\frac{3}{9}=\frac{3}{6} \times \frac{9}{3} = \frac{3}{2}$

27. Hero Group Title

But really, you're supposed to do the reciprocal then reduce in this manner: $\frac{3}{6}\div\frac{3}{9}=\frac{3}{6} \times \frac{9}{3} =\frac{1}{2} \times 3= \frac{3}{2}$

28. Hero Group Title

Show me the full steps of how you got 1.5 from 3/6 div 3/9 @andriod09

29. Hero Group Title

You must have used a calculator bro, lol

30. Hero Group Title

Because you never divide by fractions to get a decimal. Only a calculator would do that.

31. andriod09 Group Title

$\frac{3}{6}\div\frac{3}{9}=\frac{3}{6}\times\frac{9}{3}=\frac{1}{2}\times3=\frac{3}{2}$

32. andriod09 Group Title

btw, hero i literally typed all that out.

33. Hero Group Title

Good for you. Now do your original problem in the same manner.

34. cpattison Group Title

|dw:1349572930013:dw|

35. cpattison Group Title

|dw:1349573068242:dw|

36. Hero Group Title

Don't forget to reduce before executing

37. andriod09 Group Title

that doesn't help me any @cpattison

38. cpattison Group Title

|dw:1349573260282:dw|

39. cpattison Group Title

i'm trying to work this out too by the way

40. andriod09 Group Title

can you please use the $LaTeX$

41. andriod09 Group Title

just use the equation button if need be.

42. Hero Group Title

Try not to do it the hard way @cpattison

43. cpattison Group Title

$\frac{ 30(10x^2+9x+2)(3x-7) }{ 15(9x^2-4)(2x+1) }$

44. cpattison Group Title

i'm not sure i know the easy way. enlighten me?

45. Hero Group Title

First I'd have to make sure you're even doing this correctly

46. andriod09 Group Title

How is that the answer though... the answer, from the book, says that the answer is: $\frac{2(5x+2)}{3x+7}$

47. cpattison Group Title

i don't know how that happened unless we all have done something wrong. i get $\frac{ 2(25x^2-27x-14) }{ 9x^2-4 }$

48. cpattison Group Title

if i were you i would try and find someone in my class or around me to ask, and double check your equations

49. andriod09 Group Title

A)im homeschooled, B)this is me catching up

50. Hero Group Title

I was following what @cpattison did. I'm sure I would have gotten it if I had taken my own approach.

51. CliffSedge Group Title

Extremes-over-means, anyone? $\large \frac{\frac{a}{b}}{\frac{c}{d}} = \frac{ad}{bc}$

52. Hero Group Title

Yep, @cpattison made a mistake because 9x^2 - 49 is in the denominator

53. andriod09 Group Title

cliff. dafaq/dahell does that even mean????

54. Hero Group Title

|dw:1349575081973:dw|

55. Hero Group Title

$\frac{ 2(5x+2)(3x-7) }{(3x+7)(3x-7) }$

56. cpattison Group Title

oh okay. sorry for that.

57. Hero Group Title

And now the 3x - 7 reduces to: $\frac{ 2(5x+2) }{(3x+7) }$

58. CliffSedge Group Title

@andriod09 "extremes-over-means" |dw:1349575148786:dw|

59. Hero Group Title

I already know about means over extremes. I was just trying to explain it in a way that @andriod09 should have already been familiar with.

60. CliffSedge Group Title

(It's the same thing . . )

61. andriod09 Group Title

I don't understand it.... $:{$

62. Hero Group Title

You ignored the part where I said something "he should have already been familiar with".

63. CliffSedge Group Title

Meditate on it.

64. CliffSedge Group Title

I ignored nothing.

65. Hero Group Title

Normal students other than @Cliffsedge learn how to change division to multiplication by flipping the second fraction.

66. CliffSedge Group Title

It's the same thing . . .

67. CliffSedge Group Title

|dw:1349575395748:dw|

68. Hero Group Title

I know that bro, but you should have registered that I was trying to show the poor kid something he should have already been familiar with. Ask the majority of students at a school what means over extremes mean and they'll give you a blank stare.

69. cpattison Group Title

http://www.khanacademy.org/math/arithmetic/fractions/v/dividing-fractions this could help. he's great

70. CliffSedge Group Title

Anyway, I was merely offering a method that might have been recognized. It wasn't, carry on.

71. CliffSedge Group Title

@Hero , but did you notice that I didn't just pop in and say, "extremes-over-means, yo!" and leave? I gave a formula that should be immediately recognized by the more modern phrasing of "keep-flip-change." I'll just leave now, because I don't want you to continue derailing the thread just to bark at me.

72. Hero Group Title

I'm not a dog, so unfortunately I don't know how to bark.

73. cpattison Group Title

none of that helps. @andriod09 is there anything else?

74. andriod09 Group Title

yea. i would like to understand how to work the stupid fraction problem. :{

75. cpattison Group Title

did khan help at all?

76. Hero Group Title

I could have sworn I just showed you. I suppose now you need help with factoring and reducing polynomials.

77. andriod09 Group Title

cp, i don't havethe time for khan, but yes, Sam is a really good tutor. i have been to that site nealy a year now. And Hero, YES PLEASE.

78. andriod09 Group Title

@Hero are you still here??

79. satellite73 Group Title

$\frac{\frac{30x^2+27x+6}{9x^2-49}}{\frac{30x+15}{30x-70}}=\frac{30x^2+27x+6}{9x^2-49}\times \frac{30x-70}{30x+15}$

80. satellite73 Group Title

factor and cancel if you can

81. jiteshmeghwal9 Group Title

A type of complex fraction$\huge\frac{\frac{30x^2+27x+6}{9x^2-49}}{\frac{30x+15}{30x-70}}$$\LARGE{\frac{30x^2+27x+6}{9x^2-49} \div \frac{30x+15}{30x-70}}$$\LARGE{\frac{30x^2+27x+6}{9x^2-49} \times \frac{30x-70}{30x+15}}$

82. satellite73 Group Title

for example $$9x^2-49=(3x+7)(3x-7)$$

83. andriod09 Group Title

84. satellite73 Group Title

and $$30x-70=10(x-7)$$ etc etc. there will be an orgy of cancellation

85. andriod09 Group Title

can you please type that in English for me, step by step?

86. andriod09 Group Title

@jiteshmeghwal9 2 things, 1) i luv your prof pic, 2) what do i do after all that> I dont get... :{

87. jiteshmeghwal9 Group Title

bro first factor the numerators & denominators of both fractions then tell me what do u gt ?

88. andriod09 Group Title

how do i do that?

89. jiteshmeghwal9 Group Title

what u haven't studied factorization yet

90. jiteshmeghwal9 Group Title

without studying factorization u can't do this question :(

91. andriod09 Group Title

not for fractions. i can factor $x^2+10x+20$ easily. just not for fractions. plus, im homeschooled, so things aren't the same for me.

92. jiteshmeghwal9 Group Title

so factor $30x^2+27x+6$

93. jiteshmeghwal9 Group Title

@andriod09

94. andriod09 Group Title

$30x^2+27x+6$ should i find a comon factor? because i don't think there is one. buy anyway. isn't it: $2(5x+2)$

95. jiteshmeghwal9 Group Title

$ax^2+(a+b)x+b$use this identity

96. andriod09 Group Title

thas makes no sense to me. :/

97. jiteshmeghwal9 Group Title

i mean break the middle term such that the sum becomes 27x & product becomes $$30x^2*6$$

98. andriod09 Group Title

but was the answer right? it should be right.

99. jiteshmeghwal9 Group Title

but after multiplying that u r not getting the right exression

100. jiteshmeghwal9 Group Title

$30x^2+15x+12x+6$$15x(2x+1)+6(2x+1)$$(15x+6)(2x+1)$

101. andriod09 Group Title

ohhh. okay. Thanks!

102. jiteshmeghwal9 Group Title

$(3x)^2-(7)^2$$(3x+7)(3x-7)$

103. jiteshmeghwal9 Group Title

$30x-70$$10(3x-7)$

104. jiteshmeghwal9 Group Title

$30x+15$$15(2x+1)$

105. andriod09 Group Title

TYSVM i get it now!

106. andriod09 Group Title

i g2g. Bye!

107. jiteshmeghwal9 Group Title

$\frac{(15x+6)(2x+1)15(2x+1)}{(3x+7)(3x-7)10(3x-7)}$

108. jiteshmeghwal9 Group Title

bye & thanx for liking my profile profile pic