## anonymous one year ago consider this systems of equations 2/3 x +3/5 y =12 5/2 y - 3x=6 the expression that gives the value of x is... the solution for the systems of equations...

1. wolf1728

Do you know how to solve simultaneous equations?

2. anonymous

no

3. wolf1728

A) 2/3 x +3/5 y =12 B) -3x +5/2 y =6 One way is to solve for x in one equation

4. anonymous

I don't get it

5. wolf1728

B) -3x = -5/2 y + 6 We divide both sides by -3 x = 5/6 y -2

6. anonymous

options the expression that gives the value of x is... (5A/3)+(2B/5), (3A/5)-(5B/2), (5A/2)+(3B/5), (5A/3)-(2B/5), (3A/2) + (B/3)

7. UsukiDoll

mcfizzy STOP! What is that attachment?

8. anonymous

the solution to the systems of equations is (1118/47, 396/47) (33/13, 50/13) (99/13, 150/13) (8,12)

9. anonymous

@UsukiDoll what's wrong?

10. UsukiDoll

I've seen this poster (mcfizzy) posting an attachment that could be malicious. I've sent a report.

11. anonymous

okay, I probably shouldn't click on the attachment then. I'll send a report too.

12. UsukiDoll

yeah.. under his profile all of his questions answered has spam with that attachment. everyone please report this.

13. anonymous

I could use help with this problem, I'm still very confused

14. wolf1728

x = 99/13 y = 150/13

15. UsukiDoll

@wolf1728 is there to help. I have to warn everyone else about this issue as this is serious and against terms and conditions.

16. anonymous

okay thank you

17. anonymous

@wolf1728 I also need the expression that gives the value of x

18. wolf1728

Kaelyn - you do not know how to solve these so why do you need the expression for value of x ?

19. anonymous

because the question asks me to find the expression that finds the value of x, I don't want you to give me the answer just help me find the right one

20. wolf1728

I think you should find someone else to help. I'm quitting for the moment.

21. anonymous

okay thank you for your help

22. anonymous

23. anonymous

May I try?

24. UsukiDoll

go for it @waterineyes as long as it's not a direct answer

25. anonymous

26. anonymous

and @UsukiDoll I agree don't give the answer to me just help me find the answer myself

27. anonymous

Okay, don't let our interaction stop anywhere, just reply if you know or not, just be with me...

28. anonymous

okay

29. LynFran

$\frac{ 2 }{ 3 }x+\frac{ 3 }{ 4 }y=12$$\frac{ 5 }{ 2}y-3x=6$frm equation 2,$\frac{ 5 }{ 2 }y=6+3x$$y=\frac{ 2(6+3x) }{ 5 }$now sub y=2(6+3x)/5 in eq 1 $\frac{ 2 }{ 3 }x+\frac{ 3 }{ 4 }(\frac{ 2(6+3x) }{ 5 })=12$simplify and solve for x we get $\frac{ 2 }{ 3 }x+\frac{ 36+18x }{ 20 }=12$$\frac{ 40x +108+54x}{ 60 }=12$$\frac{ 94x+108 }{ 60 }=12$multiply both side of the equation we get..$94x+108=720$$94x=720-108$$x=612/94$$x=6.510638$...so y =...$y=\frac{ 2(6+3(6.510638)) }{ 5 }$$y=10.21276$..

30. anonymous

okay understanding so far

31. UsukiDoll

-_- *throws a water bottle @waterineyes

32. anonymous

Both our equations are in fraction form, we should simplify them to make a good looking equation first... Do you know how to take LCM?

33. anonymous

Hell, my net stopped working.. :(

34. anonymous

Yes I know how to take LCM

35. anonymous

Like in first equation, 15 is the LCM, so you can multiply whole equation by 15...

36. anonymous

@LynFran I am afraid you are right everywhere, but you have taken wrong fraction in very first equation,, 3/5 is good, not 3/4.. if I am not blind then.. :P Your method is good.. :)

37. UsukiDoll

if we find our y and x, keep it in fraction form. ... decimals are a pain to deal with T_T

38. UsukiDoll

*throws a canteen at @waterineyes

39. anonymous

Guys lets not throw things...

40. LynFran

o i see im sleepy lol @waterineyes goodnight u guys

41. anonymous

Goodnight @LynFran

42. anonymous

$$10x + 9y = 180$$ --- 1 This you got?

43. UsukiDoll

what is that ?

44. UsukiDoll

sigh....... the second equation is easier to deal with 2/3 x +3/5 y =12 5/2 y - 3x=6 $\frac{2}{3}x+\frac{3}{5}y=12$ $\frac{5}{2}y-3x=6$ so multiply 2 throughout the entire second equation $\frac{5}{2}y-3x=6$

45. anonymous

And this way your second equation becomes: $$5y - 6x = 12$$ --------- 2

46. UsukiDoll

uh huh

47. anonymous

@Kaelyn78 are you getting how I formed these two equations?

48. anonymous

yes I understand

49. UsukiDoll

10x + 9y = 180 5y-6x=12

50. anonymous

Thanks.. Again and again I was going above to see these equations, as you are posting in between so things are going above..

51. anonymous

you can write the second equation, other way round, x first and then y: $$10x + 9y = 180 \\ -6x + 5y = 12$$

52. anonymous

$[10x + 9y = 180 ] \times 6 = 60x + 45y = 108 \\ [-6x + 5y = 12 ] \times 10 = -60x + 50y = 120$

53. anonymous

I have multiplied the coefficient of x in second equation with first equation and same for second equation.. are you getting this step?

54. anonymous

yes I understand

55. anonymous

Now you just need to add those equations...

56. anonymous

$\cancel{60x} + 45y = 1080 \\ \cancel{-60x} + 50y = 120 \\ --------- \\95y = 2200$

57. anonymous

Sorry, that is 1080 and not 108...

58. anonymous

okay

59. anonymous

Getting previous step?

60. anonymous

yes I'm getting it

61. anonymous

Now find y, by dividing by 95 both the sides..

62. anonymous

23?

63. anonymous

Wait, I am just double checking it.. Let me take copy and pen too..

64. anonymous

It is certainly a wrong...

65. anonymous

9 multiplied by 6 is 54 not 45, just keep eyes on what I am doing, I can be wrong anywhere in writing digits. :P

66. anonymous

After Multiplying 6 and 10 the equations you will get are: $$60x + 54y = 1080 \\ -60x + 50y = 120$$ Form this you will get: $$104y = 2200$$

67. anonymous

Kill me.....

68. anonymous

1080 + 120 = 1200.. What has happened to me today.. :(

69. anonymous

@waterineyes aw sorry I can't help with that

70. anonymous

$$104y = 1200$$ Now just find y by cancelling out the things..

71. anonymous

if it's any consolation I would have gone certifiably insane trying to do this all by myself

72. anonymous

thank you

73. anonymous

$y = \frac{1200}{104}$

74. UsukiDoll

gotta reduce that fraction

75. anonymous

Do not use calculator, just cancel it out with 8, you will get in fraction..

76. anonymous

Now, put the fraction in any one of the equation above to find x...

77. anonymous

Found value of y?

78. UsukiDoll

$y=\frac{150}{13}$ 5y-6x=12 plug in y in this equation and solve for x

79. UsukiDoll

what are you talking about? I didn't post that.

80. UsukiDoll

$5(\frac{150}{13})-6x=12$

81. anonymous

@Kaelyn78 what you got for y? You break the interaction?? :(

82. anonymous

Okay, I gotta go now. If any doubt, Doll will tell you, or I will when I login next.. :) Solving these types of equations is really an easy task, just learn the concept, rest is a-jiffy work..

83. anonymous

sorry fell asleep

84. anonymous

I'm going to bed, thanks everyone, goodnight