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afvatcha
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Post subject: Number Properties Chapter 7 No. 9 ( Fourth Edition)  Posted: Sun Apr 10, 2011 2:28 pm |
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Posts: 34
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Hello,
My question is about no. 9, in chapter 7 of the Number Properties Guide.
My question is, when you clear out the X in the denominator, which X do you multiply it with? Is it the other X in the parenthesis, or the X outside the parenthesis? The other question is, what happens to the third X? The X in the denominator gets cancelled out. The second X is multiplied by the first X to give you X squared. What about the third X? In the answer it is like it doesn't exist.
X(X-(5x+6/x))=0
Thanks.
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tim
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Post subject: Re: Number Properties Chapter 7 No. 9 ( Fourth Edition) Posted: Wed Apr 13, 2011 8:16 pm |
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| ManhattanGMAT Staff |
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Location: Southwest Airlines, seat 21C
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there is no indication that the x inside the parentheses is multiplied by anything else in the parentheses. on the other hand, an x outside the parentheses means you are to multiply it by everything inside. to answer your second question, you have copied the question incorrectly. the (5x+6) should be in parentheses, as it is all over x. thus when we multiply by x the denominator goes away and the 5x-6 remains..
_________________
Tim Sanders
Manhattan GMAT Instructor
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manishdabas09
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Post subject: Re: Number Properties Chapter 7 No. 9 ( Fourth Edition) Posted: Wed Jun 01, 2011 12:34 pm |
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Hi Tim,
I have a doubt about the same question.
Here it is mentioned x(x-5x+6/x)=0 and solution is x= 6 or -1. My question is why cant we have 0 as one more solution because in case x=0 then also LHS=RHS.
Thanks in advance.
Best Regards,
Manish
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varun_783
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Post subject: Re: Number Properties Chapter 7 No. 9 ( Fourth Edition) Posted: Wed Jun 01, 2011 1:20 pm |
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Hi Manish,
If you take x=0 as a solution, you don't get 0 on the LHS. You get infinity. Remember your Maths in school, a number divided by zero is undefined or infinite, NOT 0.
Regards
Sunil
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manishdabas09
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Post subject: Re: Number Properties Chapter 7 No. 9 ( Fourth Edition) Posted: Mon Jun 06, 2011 12:45 pm |
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Many thanks for the reply Sunil ....
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varun_783
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Post subject: Re: Number Properties Chapter 7 No. 9 ( Fourth Edition) Posted: Mon Jun 06, 2011 3:59 pm |
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jnelson0612
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Post subject: Re: Number Properties Chapter 7 No. 9 ( Fourth Edition) Posted: Wed Jun 08, 2011 8:07 pm |
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Thanks Sunil!
_________________
Jamie Nelson
ManhattanGMAT Instructor
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nabil.kayani
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Post subject: Re: Number Properties Chapter 7 No. 9 ( Fourth Edition) Posted: Tue Dec 13, 2011 1:30 pm |
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can some one tell me how they did that problem step by step mathematically? I have read the solutions posted. I am still very confused. Thank you!
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tim
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Post subject: Re: Number Properties Chapter 7 No. 9 ( Fourth Edition) Posted: Sat Dec 31, 2011 1:46 pm |
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| ManhattanGMAT Staff |
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Posts: 2242
Location: Southwest Airlines, seat 21C
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Sorry, if there is already a solution out there that didn’t work for you, you’re not going to get anywhere by asking for a step by step solution because the solution that didn’t work for you IS a step by step solution. Instead, you need to tell us what you didn’t understand about the step by step solution you already read so we can help you with that..
_________________
Tim Sanders
Manhattan GMAT Instructor
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