If z^2-4<0, What is the value of z : GMAT Problem Solving (PS)
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# If z^2-4<0, What is the value of z

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If z^2-4<0, What is the value of z [#permalink]

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24 Nov 2003, 10:52
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If z^2-4<0, What is the value of z?
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Not sure if this is GMAT type material [#permalink]

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24 Nov 2003, 12:34
-2<z<2

obviously.

Solving it algebraically is tricky unless you know how to deal with inequalities using the number line test method.
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24 Nov 2003, 13:34
yes, -2<Z<2

i find number line test to be the best method for these types of problems...any other quick simple ways??
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24 Nov 2003, 13:38
think, I screwed myself here

yes, you are right..it should be -2<Z<2
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25 Nov 2003, 19:32
It's unanimous! -2<z<2. Unless we're the masses of ...
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14 Apr 2007, 06:10
What is number line test method?
How is it used?
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14 Apr 2007, 06:18
I think the answer is evident when you move the 4 over to the other side.

z^2 <4> z > -2 but < 2 , the range of values as mentioned by others is: -2<z<2
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Re: PS [#permalink]

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23 Apr 2008, 13:22
but no body explained whts a number line test method?

sabita
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Re: PS [#permalink]

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23 Apr 2008, 22:03
ann wrote:
If z^2-4<0, What is the value of z?

sabitamishra1 wrote:
but no body explained whts a number line test method?

sabita

z^2 - 4 <0
z^2 < 4
since z^2 is +ve, it is >0 but less than 4. so z must be in between -2 and 2 excluding. if you draw a line and put these values on the number line, you will see where z lies.
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Re: PS [#permalink]

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24 Apr 2008, 06:16
ann wrote:
If z^2-4<0, What is the value of z?

whats wrong with this approach?

(z+2)(z-2) < 0

z+2 < 0 or z-2 < 0

z < - 2 OR z < 2
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Re: PS [#permalink]

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03 Apr 2011, 12:21
Z^2<4

sqrt(z^2) <sqrt(4)

=> |Z|<2

=> -2<Z<2
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Re: PS [#permalink]

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03 Apr 2011, 18:19
=> (z-2)(z+2) < 0

=> -2 < z < 2
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Re: PS [#permalink]

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03 Apr 2011, 22:15
z^2<4
So z will lie between 2 and -2
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Re: PS [#permalink]

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03 Apr 2011, 22:23
Same as above

Z^2-4 < 0 add 4 to both sides
z^2 < 4 Take the square root of both sides
z < 2 and z > -2 Remember when you take the square root of an inequality, the negative sign flips the inequality

so -2<z<2
Re: PS   [#permalink] 03 Apr 2011, 22:23
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# If z^2-4<0, What is the value of z

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