## charlotteakina Group Title Help!? PLEASE! Screenshot attached! 2 questions! 1 question answered! ONE TO GO! one year ago one year ago

1. Coolsector Group Title

5 people means 3.6 seconds so y people will be t seconds we can show it this way : |dw:1350566474324:dw|

2. Coolsector Group Title

now cross multiply and get the connection between y (number of people) and t (seconds)

3. Coolsector Group Title

and hey .. how are you ? :)

4. Decart Group Title

$t=.72p$

5. Coolsector Group Title

|dw:1350566721091:dw|

6. Coolsector Group Title

if you multiply one side by 100 you should multiply the other by 100 too

7. Coolsector Group Title

we need to isolate t from the equation that i gave you

8. Coolsector Group Title

no .. it's final answer is correct but i want you to be able to get it by yourself

9. Coolsector Group Title

there is no 75 in decart's answer :|

10. Coolsector Group Title

$\frac{ 5 }{ y } = \frac{ 3.6 }{ t }$ multiply both sides by $y \times t$ we get: $5t = 3.6y$ now divide both sides of the equation by 5 we get: $t = \frac{ 3.6 }{ 5 } \times y$ which is the same as $t=0.72y$

11. Coolsector Group Title

yes sorry i was washing dishes lol

12. Coolsector Group Title

division of two fractions is like multiplying the first by the reciprocal of the second

13. Coolsector Group Title

$\frac{ a }{ b } \div \frac{ c }{ d } = \frac{ a }{ b } \times \frac{ d }{ c }$

14. Coolsector Group Title

so you can rewrite the problem as .. ?

15. Coolsector Group Title

no i just gave an example

16. Coolsector Group Title

you have to multiply the first fraction by the reciprocal of the second..

17. Coolsector Group Title

|dw:1350568226013:dw|

18. Coolsector Group Title

yes .. and changed the division to multiplication this his how you divide two fractions..

19. Coolsector Group Title

$\frac{ (x^2-x-6)(x^2+5x+4) }{ (x^2-2x-3)(x^2+x-12) }$

20. Coolsector Group Title

this is now what you have to simplify "so, do I multiply x^2 + x - 12 by x^2 + 5x + 4 now? " no.. why you say that ?

21. Coolsector Group Title

$\frac{ a }{ b } \neq a * b$

22. Coolsector Group Title

we changed the division to multiplication because we divided FRACTION BY FRACTION

23. Coolsector Group Title

no it's not right

24. Coolsector Group Title

$\frac{ 5 }{ 3 } * \frac{ 4 }{ 2 } = ?$

25. Coolsector Group Title

26. Coolsector Group Title

right you just multiplied 5 with 4 and divided by the multiplication of 3 with 2

27. Coolsector Group Title

|dw:1350569102823:dw|

28. Coolsector Group Title

so same here .. after we changed the division into multiplication it's just multiplication of two fractions

29. Coolsector Group Title

you tell me .. how do we multiply those two fractions ?

30. Coolsector Group Title

i wont get mad why would i :| look : $\frac{ x^2-x-6 }{ x^2-2x-3 } \times \frac{ x^2+5x+4 }{ x^2+x-12 } = \frac{ (x^2-x-6)(x^2+5x+4) }{ (x^2-2x-3)(x^2+x-12) }$

31. Coolsector Group Title

i dont know why you multiply numerator by denominator

32. Coolsector Group Title

this is what you get after the multiplication of the two fractions now we better factor every term than open the brackes like x^2-x-6 = x^2-3x+2x-6 = x(x-3)+2(x-3) = (x+2)(x-3)

33. Coolsector Group Title

yes look : whenever there is multiplication of two fractions you multiply numerator by numerator and denom by denom.. whenever there is division of two fractions you keep the first fraction as it is you change the division into multiplication but then for the second fraction you flip numerator and denominator and then you have multiplication of two fractions..

34. Coolsector Group Title

yes as i wrote up there

35. LCK Group Title

I'll just to butt in for a bit, the general flow of fraction division goes like this: 1. Turn the division into a multiplication by inverting the second fraction 2. Factorise as much as possible and eliminate common terms. 3. Solve by multiplying the numerator by the numerator and denominator by denominator. Yes I wrote the same thing as cool sorry :/.

36. Coolsector Group Title

now it's better to factor every term than open the brackets .. so factoring x^2-x-6 gives = x^2-3x+2x-6 = x(x-3)+2(x-3) = (x+2)(x-3)

37. Coolsector Group Title

can you factor the rest of the terms ?

38. Coolsector Group Title

yes.. i just showed the way

39. Coolsector Group Title

you see my last expression is (x+2)(x-3)

40. Coolsector Group Title

now factor the rest of the terms .. what do you get ?

41. Coolsector Group Title

so are you factoring the rest ?

42. Coolsector Group Title

good so how the expression looks like ?

43. Coolsector Group Title

after you change every term by it's factored form

44. Coolsector Group Title

you have to replace every term by it's factored from like replaceing " x^2 - x- 6" by " (x+2)(x-3) " in the last expression

45. Coolsector Group Title

very good

46. Coolsector Group Title

now you can eliminate some of them..

47. Coolsector Group Title

if you have the same thing in the numerator and in the denominator you can eliminate it ..

48. Coolsector Group Title

and one more ..

49. Coolsector Group Title

|dw:1350571449666:dw|

50. Coolsector Group Title

so what is left .. $\frac{ x+2 }{ x-3 }$

51. Coolsector Group Title

yes

52. Coolsector Group Title

yw :)

53. Coolsector Group Title

i hope the next question of this kind will be easier for you now that you know the steps

54. Coolsector Group Title