## francescazares2012 2 years ago What would y be? ^3√(3y+3)=3

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1. Dido525

Well the idea is to isolate y right? What would be your first step?

2. Dido525

You have a cube root. How would you get rid of that?

3. Dido525

For instance, if you have a square root you have to square to get rid of the square root.

4. Dido525

@francescazares2012 : You there?

5. francescazares2012

yes

6. francescazares2012

So I would cube both sides?

7. Dido525

Yep!

8. francescazares2012

9. Dido525

Good job!

10. francescazares2012

It didn't work. :/

11. francescazares2012

12. Dido525

Ohh wait. I am dumb.

13. Dido525

3^3 is 27 >.< .

14. francescazares2012

thanks for your help! I was having so much trouble

15. Dido525

Yeah it's 8 :P .

16. francescazares2012

could you help me with another?

17. Dido525

Sure.

18. francescazares2012

√(x+10)=x+10

19. Dido525

Okay, square both sides again :) .

20. francescazares2012

okay so now i have x+10=(x+10)^2

21. Dido525

Can you expand the (x+10)^2 ?

22. francescazares2012

yes

23. Dido525

|dw:1355462739047:dw|

24. francescazares2012

okay I am a bit confused

25. Dido525

With?

26. francescazares2012

what I am supposed to do

27. Dido525

Okay so we have: |dw:1355462917095:dw|

28. Dido525

|dw:1355463044826:dw|

29. francescazares2012

okay I sort of see where this is going

30. Dido525

You realize we have to foil this correct?

31. Dido525

|dw:1355463252789:dw|

32. francescazares2012

okay

33. Dido525

What did you get?

34. francescazares2012

-10 and -9?

35. Dido525

Very good! :) .

36. francescazares2012

wow!

37. Dido525

Algebra isn't that bad once you get the hang of it :) .

38. francescazares2012

I have a algebra final tomorrow. I am pretty nervous.

39. Dido525

Haha, you will be fine ^_^ .

40. francescazares2012

I am working on this problem right now and I got 3 but it says it's wrong. √(6a-2)=16

41. francescazares2012

not 16 I meant -4

42. francescazares2012

so √(6a-2)=-4

43. Dido525

So square both sides :) .

44. Dido525

Keep the negative inside the brackets when you square, so it would be like (-4)^2 .

45. francescazares2012

but wouldn't that be 16?

46. Dido525

Yep :) .

47. Dido525

A genral rule is when you square both sides and the negative it attached to a number, You put the negative in brackets and them square it.

48. Dido525

Because when you square you are basically going -4 * -4 which his 16 ( negative * negative is +) .

49. francescazares2012

Okay. Well I got the final answer to be 3. But it says that that is wrong. Why is that?

50. Dido525

So when you square both sides, what did you get?

51. Dido525

It's strange, that's absolutely correct.

52. francescazares2012

That's what I thought. It's online hw. And it tells you when it's right or wrong.

53. francescazares2012

nevermind it was does not exist

54. francescazares2012

probably because it was a -4

55. Dido525

No, that's not why.

56. Dido525

It depends on the sign of the square root.

57. Dido525

If it's a POSITIVE square root then yes, no solutions exist.

58. Dido525

But if it's -√(6a-2) then it's 3.

59. Dido525

Because when you take the square root of a function it's always in the form of ±√ f(x) . We need to know the proper sign.

60. Dido525

61. francescazares2012

You can say that again!

62. Dido525

Anything else?

63. francescazares2012

Only if you are up for it!

64. francescazares2012

√(x+6)=√(x)-6

65. Dido525

Square both sides :P .

66. francescazares2012

67. Dido525

It's a procedure essentially :P .

68. Dido525

What did you get?

69. francescazares2012

does not exist

70. Dido525

Good job!

71. francescazares2012

√(y+1)=√(y)+1

72. francescazares2012

73. Dido525

Square both sides :) .

74. francescazares2012

okay

75. francescazares2012

y+1=y+1?

76. Dido525

No....

77. Dido525

We have: |dw:1355464812127:dw|

78. Dido525

You square the WHOLE thing :) .

79. francescazares2012

oh okay

80. francescazares2012

so what do i do now?

81. Dido525

After squaring both sides?

82. francescazares2012

yes

83. Dido525

Get all the y's on one side.

84. francescazares2012

I think I am having trouble squaring them.

85. Dido525

|dw:1355465159249:dw|

86. francescazares2012

oh so I foil

87. Dido525

You should get the same answer no matter what you use.

88. francescazares2012

oh okay

89. Dido525

What did you do?

90. francescazares2012

I am moving the y's

91. francescazares2012

I think I am doing this wrong