anonymous one year ago Solve -2(2x + 5) - 3 = -3(x - 1). 16 -16 -10 -13

1. anonymous

@billj5 , @Michele_Laino

2. anonymous

So you are solving for x. Meaning you need to isolate the x-variable. What is your understanding of this Q so far?

3. anonymous

ok start by distributing again

4. anonymous

^ Must use the distributive property first. (To get rid of those complex parenthesis!)

5. anonymous

You need to use the distributive property on both sides of the equation first. -2(2x+5) and -3(x-1)

6. Michele_Laino

yes! If we apply the distributive property of multiplication over addition at both sides, we get: -4x -10 -3 = -3x +3

7. anonymous

I'm not sure I can correctly distribute this question

8. anonymous

so now what do we do?

9. anonymous

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10. anonymous

Combine like terms.

11. Michele_Laino

what is: -10-3=...?

12. anonymous

-7

13. anonymous

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14. Michele_Laino

no, it is: -10 -3 = -13

15. anonymous

When you're in debt by \$10, and get another loan for \$3, you're in a total of 13\$ of debt.

16. anonymous

Oh okay.

17. anonymous

Now isolate the x from either side… you'll still get the same answer regardless of which side you isolate the x with. (I'd go with the easier side)

18. anonymous

IF you do it correctly^^

19. anonymous

How would I do that?

20. anonymous

divide right?

21. anonymous

You should then get -4x-10=-3x+3 Then get variables and constants on different sides of equation -4x+3x=3+10 -1x = 13 Divide both sides by -1 Your answer should be x = -13 or D

22. anonymous

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23. anonymous

Now what do you do?

24. anonymous

divide ?

25. Michele_Laino

try to subtract 7x from both sides, please

26. anonymous

No, subtract three from both sides then you can divide. (Remember we CANNOT divide/multiply if there are other constants)

27. anonymous

Oh, would you like me to do it the other way? @Michele_Laino

28. Michele_Laino

sorry you are right! @Aureyliant

29. anonymous

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30. anonymous

Now what do you get? @FEARLESS_JOCEY

31. anonymous

Absolutely!

32. anonymous

Sorry I ran out of room but we're almost done… We would get: -16 = 7x

33. anonymous

Wait… did I do something wrong? The answer isn't in any of the answer choices.

34. anonymous

okay, and we divide right?

35. anonymous

Yes :)

36. anonymous

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37. anonymous

I'm not to sure how to divide it when it is a negative number.

38. anonymous

@Aureyliant I think you messed up somewhere because there is no way that the answer is -2 @FEARLESS_JOCEY look back at my comment and look at how io explained it i got the correct answer

39. anonymous

Yes… you did. The answer is x = -16. I checked my work and I didn't see anything incorrect.

40. anonymous

@Michele_Laino Do you see where I may have gone wrong?

41. anonymous

if you divide -16 by 7 you get -2.28 You went wrong by adding positive 4x to -3x and getting positive 7x when it should have been positive 1x

42. anonymous

@Aureyliant

43. Michele_Laino

I'm pondering...@Aureyliant

44. anonymous

You're supposed to take the inverse of -4x = +4x. When you take it to the other side of the equation, it must become the opposite sign.

45. anonymous

Oh! I see where i went wrong. It was supposed to be -3x + 4x = 1x.

46. anonymous

I understand that but -3x did not change signs and it should have become 1x instead of positive 7x You also subtracted -3 from -10 and got 013 and then you subtracted -3 again

47. anonymous

I forgot the negative three. I apologize.

48. Michele_Laino

I got thise expression: -4x-13=-3x+3 then adding 4x to both sides, we get: -13=x+3

49. Michele_Laino

this*

50. anonymous

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51. anonymous

See you guys are forgetting to cross out the three after you have moved it to the opposite side of the equation and you are ending up with an extra 3

52. anonymous

I sincerely apologize… I've never made this kind of silly mistake before

53. anonymous

Great job catching my mistake though Vet! :)

54. Michele_Laino

no worries :) @Aureyliant

55. anonymous

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56. anonymous

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57. anonymous

No problem! I make those kinds of mistakes every once in a while as well. I always re check my work! @FEARLESS_JOCEY do you understand what the correct answer is

58. anonymous

@Aureyliant you have already moved the -3 over to get -13 you do not need to subtract it again to get -16

59. anonymous

I understand it.

60. anonymous

No… I didn't. The answer is B.

61. anonymous

I'm not sure if it is B or D now. Lol, I'm so confused

62. anonymous

It's 100% B. I didn't already subtract 3 to get -13… that was an earlier step with another -3. http://prntscr.com/7e7rjb

63. anonymous

I think they set it up that way to make it confusing for the student.

64. anonymous

@Aureyliant look back at your quation you subracted 3 to get -13, but then you subtracted the 3 again to get -16 but you are not suppossed to because you gave already used it

65. anonymous

No, that was when I was combining like terms after distribution.

66. anonymous

-3 was already there since the beginning.

67. anonymous

There are 2 "-3"s

68. anonymous

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69. anonymous

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70. anonymous

Look… Let me do the problem again.

71. anonymous

OMG you are so right I am so sorry i feel like a moron! @FEARLESS_JOCEY the answer is B

72. anonymous

@Aureyliant

73. anonymous

You don't need to work it out again I understand where i messed up

74. anonymous

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75. anonymous

Too late haha :)

76. anonymous

Such a long thread. Well that's all for now… TEAMWORK! Hope this helped, Jocey! :)

77. anonymous

Tag me if you need any more help.

78. anonymous

okay I will. THANKS GUYS!