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What is the value of y? [#permalink]
 22 Feb 2012, 19:51
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What is the value of y? (1) 3|x^2 – 4| = y – 2 (2) |3 – y| = 11
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Re: What is the value of y? [#permalink]
22 Feb 2012, 21:50
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Re: What is the value of y? (1) 3|x2 – 4| = y – 2 (2) |3–y|=11 [#permalink]
23 Apr 2012, 22:33
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C for sure is the answer , Bunuel your explanations are simply awsome. Thanks
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Re: What is the value of y? (1) 3|x2 – 4| = y – 2 (2) |3–y|=11 [#permalink]
28 Apr 2012, 11:01
Answer C, Bunuel's explaination has definitely helped me better understand absolute value questions.
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Re: What is the value of y? [#permalink]
05 Jul 2012, 11:52
Bunuel wrote: What is the value of y?
(1) 3|x^2-4|=y-2. Now, since we are asked to find the value of y, from this statement we can conclude only that y\geq{2}, as LHS is absolute value which is never negative, hence RHS als can not be negative. Not sufficient.
(2) |3 - y| = 11:
y<3 --> 3-y=11 --> y=-8;
y\geq{3} --> -3+y=11 --> y=14.
Two values for y. Not sufficient.
(1)+(2) Since from (1) y\geq{2}, then from (2) y=14. Sufficient.
Answer: C.
Hope it's clear. Sorry I can't to figure out why y >= 2........ 1) 3x^2 - 4 = y-2 and -3x^2 + 4 = y-2 and then ??'  thanks
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Re: What is the value of y? [#permalink]
05 Jul 2012, 11:57
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carcass wrote: Bunuel wrote: What is the value of y?
(1) 3|x^2-4|=y-2. Now, since we are asked to find the value of y, from this statement we can conclude only that y\geq{2}, as LHS is absolute value which is never negative, hence RHS als can not be negative. Not sufficient.
(2) |3 - y| = 11:
y<3 --> 3-y=11 --> y=-8;
y\geq{3} --> -3+y=11 --> y=14.
Two values for y. Not sufficient.
(1)+(2) Since from (1) y\geq{2}, then from (2) y=14. Sufficient.
Answer: C.
Hope it's clear. Sorry I can't to figure out why y >= 2........ 1) 3x^2 - 4 = y-2 and -3x^2 + 4 = y-2 and then ??' thanks We are given that 3|x^2-4|=y-2. Now, the left hand side in this expression ( 3|x^2-4|) is an absolute value, so it cannot be negative, so the right hand side of the expression ( y-2) must also be non-negative: y-2\geq{0} --> y\geq{2}. Hope it's clear.
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Re: What is the value of y? [#permalink]
03 Oct 2012, 20:05
pls point out if i am wrong
1.
3(x^2- 4) = y- 2
and 3(x^2-4)= - (y-2)
y=-4
y=-16
from 2
y = 8
y= 14
so e is the answer
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Re: What is the value of y? [#permalink]
04 Oct 2012, 01:29
Archit143 wrote: pls point out if i am wrong
1.
3(x^2- 4) = y- 2
and 3(x^2-4)= - (y-2)
y=-4
y=-16
from 2
y = 8
y= 14
so e is the answer from 2 y = 8 - should be y = -8; |3-8| = |-5| = 5 and not 11; |3-(-8)| = |3+8| = 11 y= 14 3(x^2- 4) = y-2 it should be 3|x^2-4|=y-2 if y-2\geq0.
and 3(x^2-4)= -(y-2) it should be 3|x^2-4|=-(y-2) if y-2<0
but we don't have any information about y.
y=-4
y=-16 No justification for these values, we don't know what is the value of x.Statement (1) is not sufficient. Statement (2) provides two possible values for y, not sufficient. Taken together (1) and (2): since y-2 equals an absolute value, it should be non-negative. Only y = 14 is acceptable. Sufficient, therefore answer C.
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Re: What is the value of y? [#permalink]
20 Oct 2012, 13:01
nitzz wrote: What is the value of y?
(1) 3|x2 – 4| = y – 2
(2) |3 – y| = 11 1) x can be any number and hence we can substitute any number of x and get various values for y. Insufficient 2) y can either be 14 or -8. Insufficient 1 & 2 together. | x2 – 4| should be positive since modulus cannot take negative values. So \frac{y-2}{3} should be positive. So y is 14. Answer is C
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Re: What is the value of y? [#permalink]
20 Oct 2012, 15:38
I'm not completely sure about your explanation though I have obtained C like answer If someone can explain this question better, go ahead 
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Re: What is the value of y? [#permalink]
20 Oct 2012, 23:58
carcass wrote: I'm not completely sure about your explanation though I have obtained C like answer If someone can explain this question better, go ahead If you could tell me what is worrying about my explanation, I would be pleased to clear it up.
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Re: What is the value of y? [#permalink]
06 Apr 2013, 11:35
Bunuel,
I understand from statement 1 we get y>=2 , but when we combine both statements together we get y>=2 and y=14. Now how can we just assume y to be 14, because y can also take the value of 2 right .
I chose E on this basis .
Thanks
TT
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Re: What is the value of y? [#permalink]
06 Apr 2013, 15:11
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thinktank wrote: Bunuel,
I understand from statement 1 we get y>=2 , but when we combine both statements together we get y>=2 and y=14. Now how can we just assume y to be 14, because y can also take the value of 2 right .
I chose E on this basis .
Thanks
TT That's not correct. Y cannot be 2, otherwise the second equation would not be true. |3-2|=11, 1=11 As you can see if we pick 2, the second equation is not verified. If take a look at the explanations above, you'll find out that statement 2 defines two possible vaules for y (-8,14)[ not enough to say the value of y]; and that statement 1 is true only for y>=2, because 3|x^2-4|=y-2, the left part is always >=0 (thanks to the abs value), and so the right part must be >=0 too. If we merge those conditions: y=-8 or y=14 with y>=2, the only value that y can have is 14 Hope it's clear now
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Re: What is the value of y? [#permalink]
28 Apr 2013, 15:17
I know this is not needed for this problem but can someone show me how to solve 3|x^2 - 4| = y-2 from statement 1? Like what are the equations you could form if you tried to isolate y in this example?
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Re: What is the value of y? [#permalink]
29 Apr 2013, 02:08
jmuduke08 wrote: I know this is not needed for this problem but can someone show me how to solve 3|x^2 - 4| = y-2 from statement 1? Like what are the equations you could form if you tried to isolate y in this example? We have y = 2+3|x^2-4|Case I: x>2 --> We can remove the modulus sign as it is and y = 2+3(x^2-4) = 3x^2-10Case II : -2<x<2 --> y = 2+3(4-x^2) = 14-3x^2Case III : x<-2 Just as in Case I; y = 3x^2-10For x=2 or x=-2, y = 2.
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DS Absolute value equation: What is the value of y? [#permalink]
29 Apr 2013, 12:00
What is the value of y? (1) 3|x^2 – 4| = y – 2 (2) |3 – y| = 11
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Re: DS Absolute value equation: What is the value of y? [#permalink]
29 Apr 2013, 12:56
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Re: DS Absolute value equation: What is the value of y?
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