## mlbach Group Title 13x=7x+5 one year ago one year ago

1. PhoenixFire Group Title

Solve for x?

2. mlbach Group Title

yes, i dont even know where to start!!!!

3. zzr0ck3r Group Title

subtract 7x from both sides and tell me what you got

4. rainbow22 Group Title

5/6

5. rainbow22 Group Title

=x

6. zzr0ck3r Group Title

7. PhoenixFire Group Title

$13x=7x+5$ Subtract 7x from both sides. $13x-7x=7x-7x+5$ Combine like terms $6x=5$ Divide both sides by 6 $x={5 \over 6}$

8. zzr0ck3r Group Title

we are not saposed to give them the answers, you should involve them in getting the answer...

9. PhoenixFire Group Title

Sorry @zzr0ck3r I'll remember for next time.

10. mlbach Group Title

AHHHHH..Thank you so much Phoenixfire for explaining!!!

11. mlbach Group Title

X-2/5=1/2

12. mlbach Group Title

how would i start this one?

13. PhoenixFire Group Title

Add 2/5 to both sides. What do you get?

14. mlbach Group Title

im horrible at this!!! add 2/5 to 2/5 and 1/2?

15. PhoenixFire Group Title

Yes. type out the entire equation with 2/5 added to both sides.

16. PhoenixFire Group Title

@mlbach Did you get it?

17. mlbach Group Title

no, im sorry, trying to do it on paper

18. mlbach Group Title

im 38 and math is like a foreign language to me!

19. PhoenixFire Group Title

You have $x-{2 \over 5}={1 \over 2}$ So, add 2/5. You get: $x-{2 \over 5}+{2 \over 5}={1 \over 2}+{2 \over 5}$ Try solve from there.

20. mlbach Group Title

x-4/5=9/10

21. mlbach Group Title

is that right...9/10

22. PhoenixFire Group Title

You can see that the -2/5+2/5 results in 0. $x-0={1 \over 2}+{2 \over 5}$ But you got the right hand side correct.

23. mlbach Group Title

ok, they cancel each other out right?

24. PhoenixFire Group Title

Correct! So, $x={9 \over 10}$

25. mlbach Group Title

YAY!!!!! thank you!!!

26. PhoenixFire Group Title

No problem. :) Any other problems?

27. mlbach Group Title

2/7X=6

28. PhoenixFire Group Title

${2 \over 7}x=6$ Divide both sides by 2/7. The one the left will cancel and then you're left with x=??

29. mlbach Group Title

how do i know that im dividing?

30. PhoenixFire Group Title

${2 \over 7}x=6$ Divide by 2/7${{{2 \over 7}x} \over {2 \over 7}}={6 \over {2 \over 7}}$

31. PhoenixFire Group Title

${{2 \over 7} \over {2 \over 7}}=1$ Do you understand that? Anything divided by itself is 1.

32. mlbach Group Title

yes

33. mlbach Group Title

i just dont know how to do 6 divided by 2/7

34. PhoenixFire Group Title

So, that leave $1x={6 \over {2 \over 7}}$ Now, a trick is to dividing by fractions: ${a \over {b \over c}}={{c \over b}a}$ You flip the bottom fraction and multiply the top by it. Giving you: ${6 \over {2 \over 7}}={7 \over 2}6$ Or ${7*6} \over 2$

35. PhoenixFire Group Title

36. mlbach Group Title

21?

37. PhoenixFire Group Title

Yes! $x=21$

38. mlbach Group Title

can i just put you in my pocket and and take you to class with me?

39. PhoenixFire Group Title

Hahaha. Yes, if you have a cell phone and internet on it. :)

40. mlbach Group Title

lol

41. mlbach Group Title

A telephone book has white pages and yellow pages. ¾ of the book consists of the white pages; the yellow pages number 300. What is the total number of pages in the telephone book?

42. mlbach Group Title

how would i start this one

43. PhoenixFire Group Title

White=3/4 of the book Yellow=1/4 of the book. So, if 1/4 of the book is 300. How many total pages are there?

44. mlbach Group Title

900

45. PhoenixFire Group Title

Almost. Y=yellow=1/4=300 W=white=3/4=300*3 T=total=W+Y=(300*3)+300=1200

46. mlbach Group Title

ah. i got it

47. mlbach Group Title

A theater usher at a Broadway musical finds that ½ of the patrons attending a performance are in their seats by show time. The remaining 60 people are seated after the opening number. If the show is always a complete sellout, how many seats does the theater have?

48. PhoenixFire Group Title

This one is mostly a play on words. If you single out a few words: "1/2", "remaining", "sellout" From this you can see that "sellout" says all seats are taken. "remaining" means those not seated initially. "1/2" the initial people seated. So, if "half" of the attendees are seated before the show, and the "remaining" are seated after the first number. How many seats are there in the theater which is "sold out (ie all seats taken)"?

49. PhoenixFire Group Title

*** "remaining 60" ***

50. mlbach Group Title

120?

51. PhoenixFire Group Title

Correct!

52. mlbach Group Title

YAY!!!! lol

53. PhoenixFire Group Title

Getting the hang of it?

54. mlbach Group Title

right now i am, but come test time, I'll draw a blank!

55. mlbach Group Title

Of those invited to a wedding, 2/7 were friends of the bride. The friends of the groom numbered 65. How many people were invited to the wedding

56. PhoenixFire Group Title

Haha. Of course. Nobody can avoid the blank come test time.

57. mlbach Group Title

unfortunatley not!

58. mlbach Group Title

what do i look at first?

59. PhoenixFire Group Title

bride=2/7 Therefore, groom=5/7=65 You can take this known number as a percentile of the total attendees. ${5 \over 7}T=65$ Where T= the total number of people attending. Now solve for T.

60. mlbach Group Title

where did you get 5/7 from?

61. PhoenixFire Group Title

Well if the brides guests are 2/7 of the attending people. then the grooms is the remaining guests. Correct? so 1-2/7 = 5/7

62. mlbach Group Title

oh ok

63. PhoenixFire Group Title

To solve for T you use the same method as one of the other problems above. The funny trick with dividing by fractions.

64. PhoenixFire Group Title

Got it yet?

65. mlbach Group Title

not quite

66. PhoenixFire Group Title

What are you stuck on?

67. mlbach Group Title

5/7T=65....i get stuck on how to work the problem out

68. PhoenixFire Group Title

Well you want to isolate T. Because that's the unknown variable that you want to become known. So in this case, the only way to do that is to remove the 5/7 from T. You will want to divide by 5/7 to make it cancel out, leaving T alone on the left.

69. mlbach Group Title

so do i divide both sidesby 5/7?

70. mlbach Group Title

71. PhoenixFire Group Title

Yes. Because if you change the equation on the left, you have to change it in the same way on the right for the equality to hold. 91 is correct!

72. mlbach Group Title

awesome!!!!

73. mlbach Group Title

thank you so much for your help, I appreciate it!

74. PhoenixFire Group Title

No problem at all. Become a fan of me, and if you need help just send me a message.

75. mlbach Group Title

Done!