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# What is the value of x^2yz − xyz^2, if x = − 2, y = 1, and z = 3?

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Math Expert
Joined: 02 Sep 2009
Posts: 60460
What is the value of x^2yz − xyz^2, if x = − 2, y = 1, and z = 3?  [#permalink]

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10 Jan 2016, 07:27
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5% (low)

Question Stats:

95% (00:45) correct 5% (01:00) wrong based on 883 sessions

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What is the value of $$x^2yz − xyz^2$$, if x = − 2, y = 1, and z = 3?

(A) 20
(B) 24
(C) 30
(D) 32
(E) 48

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Re: What is the value of x^2yz − xyz^2, if x = − 2, y = 1, and z = 3?  [#permalink]

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11 Jan 2016, 06:54
Given : x = − 2, y = 1, and z = 3

x^2yz − xyz^2,
= xyz (x- z)
= (-2)(1)(3) [ (-2) - 3]
= (-6)*(-5)
= 30
Hence C.
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Re: What is the value of x^2yz − xyz^2, if x = − 2, y = 1, and z = 3?  [#permalink]

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11 Jan 2016, 19:43
4*1*3 -(- 2*1*9)
=12+18 = 30

Ans: C
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Joined: 23 Apr 2016
Posts: 6
Re: What is the value of x^2yz − xyz^2, if x = − 2, y = 1, and z = 3?  [#permalink]

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21 May 2016, 07:41
can someone please explain this a bit more? I just substituted and definitely didnt come close
Math Expert
Joined: 02 Aug 2009
Posts: 8341
Re: What is the value of x^2yz − xyz^2, if x = − 2, y = 1, and z = 3?  [#permalink]

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21 May 2016, 07:45
2
JSS16 wrote:
can someone please explain this a bit more? I just substituted and definitely didnt come close

Hi,

the Q is --- What is the value of x^2yz − xyz^2, if x = − 2, y = 1, and z = 3? ..

$$x^2yz − xyz^2 = xyz(x-z) = (-2)*1*3*(-2-3) = (-2)*1*3*(-5) = 1*3*10=30$$...
C
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Re: What is the value of x^2yz − xyz^2, if x = − 2, y = 1, and z = 3?  [#permalink]

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21 May 2016, 10:58
1
Bunuel wrote:
What is the value of x^2yz − xyz^2, if x = − 2, y = 1, and z = 3?

(A) 20
(B) 24
(C) 30
(D) 32
(E) 48

$$x^2$$$$yz$$ = $$-2^2$$$$(1*3)$$ => 12

$$xy$$$$z^2$$ = $$(-2*1)3^2$$ => -18

So, $$x^2$$$$yz$$ − $$xy$$$$z^2$$ = 12 - (-18) => 30

Hence answer will be (C) 30
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Joined: 18 Aug 2016
Posts: 1
Re: What is the value of x^2yz − xyz^2, if x = − 2, y = 1, and z = 3?  [#permalink]

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11 Oct 2016, 23:33
Bunuel wrote:
What is the value of x^2yz − xyz^2, if x = − 2, y = 1, and z = 3?

(A) 20
(B) 24
(C) 30
(D) 32
(E) 48

The confusion created in this question is that they could have included brackets.

ie (x^2)yz - xyz^2..

Else people like me will take x^(2yz)-xyz^2.

Is there any rule for this? Please tell me if so.
Math Expert
Joined: 02 Sep 2009
Posts: 60460
Re: What is the value of x^2yz − xyz^2, if x = − 2, y = 1, and z = 3?  [#permalink]

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12 Oct 2016, 00:02
1
wolf020287 wrote:
Bunuel wrote:
What is the value of x^2yz − xyz^2, if x = − 2, y = 1, and z = 3?

(A) 20
(B) 24
(C) 30
(D) 32
(E) 48

The confusion created in this question is that they could have included brackets.

ie (x^2)yz - xyz^2..

Else people like me will take x^(2yz)-xyz^2.

Is there any rule for this? Please tell me if so.

x^2yz mathematically can only mean x^2*y*z. If it were 2 to the power of 2yz, then it would be written as x^(2yz). Still edited the original post to avoid confusion.
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Re: What is the value of x^2yz − xyz^2, if x = − 2, y = 1, and z = 3?  [#permalink]

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12 Oct 2016, 02:03
Bunuel wrote:
What is the value of $$x^2yz − xyz^2$$, if x = − 2, y = 1, and z = 3?

(A) 20
(B) 24
(C) 30
(D) 32
(E) 48

$$(-2)^2*1*3 − (-2)*1*3^2$$

=4*1*3 - ( -2)*1*9
= 12 - (-18)
= 30

Hence answer will be (C) 30

_________________
Thanks and Regards

Abhishek....

PLEASE FOLLOW THE RULES FOR POSTING IN QA AND VA FORUM AND USE SEARCH FUNCTION BEFORE POSTING NEW QUESTIONS

How to use Search Function in GMAT Club | Rules for Posting in QA forum | Writing Mathematical Formulas |Rules for Posting in VA forum | Request Expert's Reply ( VA Forum Only )
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What is the value of x^2yz − xyz^2, if x = − 2, y = 1, and z = 3?  [#permalink]

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11 Apr 2017, 22:59
For this question, you must to remember that you need to factor common terms out, then it's just plug and play, and obviously, avoid silly mistakes (I'm talking directly to myself here!) and go bit by bit, just like Jack the Ripper:

$${ x }^{ 2 }yz-xy{ z }^{ 2 }=\\ xyz\left( x-y \right) =\\ \left[ \left( -2 \right) \left( 1 \right) \left( 3 \right) \right] \left( -2-3 \right) =\\ \left( -6 \right) \left( -5 \right) =\\ 30$$
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Re: What is the value of x^2yz − xyz^2, if x = − 2, y = 1, and z = 3?  [#permalink]

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06 Sep 2018, 08:28
1
xyz(x-z)
(-2)(1)(3)(-2-3)
(-6)(-5)
30
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Re: What is the value of x^2yz − xyz^2, if x = − 2, y = 1, and z = 3?  [#permalink]

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14 May 2019, 06:06
1
=> x= -2, y = 1, z = 3,

=> xyz[x-z]

=> (-2)(1)(3)(-2-3)

=> (-6)(-5)

=> 30
Re: What is the value of x^2yz − xyz^2, if x = − 2, y = 1, and z = 3?   [#permalink] 14 May 2019, 06:06
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