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notgoodinmath
- Junior | Next Rank: 30 Posts
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- Joined: Tue Jul 08, 2008 1:29 pm
Are you sure about the question?notgoodinmath wrote:If x(squared)+7x-3=4
what is the absolute value of lp-ql?
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i think that p and q are the 2 roots of the equation which he has missed to write while posting.
If we assume that p and q are the 2 roots of the equation then the answer goes as follows:
x^2 + 7x -3 = 4
=> x^2 + 7x -7 = 0
hence the roots are [-7+sqrt(7^2 - 4*1*(-7))]/2*1 and [-7-sqrt(7^2 - 4*1*(-7))]/2*1
hence [-7 + sqrt(77)]/2 and [-7 -sqrt(77)]/2 .
so |p-q| = [-7 +sqrt(77) +7 + sqrt(77)]/2 = 2* sqrt(77)/2 = sqrt(77)
Hope this is the answer that notgoodinmath was looking for.
If we assume that p and q are the 2 roots of the equation then the answer goes as follows:
x^2 + 7x -3 = 4
=> x^2 + 7x -7 = 0
hence the roots are [-7+sqrt(7^2 - 4*1*(-7))]/2*1 and [-7-sqrt(7^2 - 4*1*(-7))]/2*1
hence [-7 + sqrt(77)]/2 and [-7 -sqrt(77)]/2 .
so |p-q| = [-7 +sqrt(77) +7 + sqrt(77)]/2 = 2* sqrt(77)/2 = sqrt(77)
Hope this is the answer that notgoodinmath was looking for.
I actually got this question on my gmat test and like you guys I was :roll: ....some answers I received in other websites tell me this:
x (squared) is the constat variable p= 1
and q is -3 + (-4)= -7
so the absolute value of lp-ql=8
x (squared) is the constat variable p= 1
and q is -3 + (-4)= -7
so the absolute value of lp-ql=8
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Stuart@KaplanGMAT
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That's crazytalk!notgoodinmath wrote:I actually got this question on my gmat test and like you guys I was :roll: ....some answers I received in other websites tell me this:
x (squared) is the constat variable p= 1
and q is -3 + (-4)= -7
so the absolute value of lp-ql=8
There's no set accepted mathematical definition along those lines. I refuse to believe that the question, as written, appears on the GMAT, if for no other reason than it's redundant (you'd never write out "absolute value" and also use the |x| notation - that's like saying "what's the positive value of +4").
Stuart Kovinsky | Kaplan GMAT Faculty | Toronto
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Stuart@KaplanGMAT
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- Thanked: 1710 times
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Are you sure that the question didn't start with something like:notgoodinmath wrote:that was my bad- I was just trying to make sure ppl knew it was the absolute value-sorry
"If p and q are the roots of ...."?
Without such a statement, p and q are undefined - I'm really finding it hard to believe that the GMAT would have such an ambiguous question.
Stuart Kovinsky | Kaplan GMAT Faculty | Toronto
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