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If m and n are the roots of the equation [#permalink]
18 Aug 2018, 00:39
HI guys!
Question:
If m and n are the roots of the equation \(a^2  6a + 8 = 0\), then find the value of \((m+n)(mn)\)
A. 12
B. 8
C. 16
D. 4
E.18
Now, the answer should be 12, because the fractioning of the equation gets me (a4) (a2). However, what if I switched places here and put (a2) (a4). Then, m = 2 and n=4, thus (2+4) (24) = 12. Where am I going wrong? Sorry for this stupid question. And btw, roots of the equation are always positive then, right?
Appreciate any help.
Last edited by Carcass on 18 Aug 2018, 02:03, edited 1 time in total.
Edited by Carcass




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Re: If m and n are the roots of the equation [#permalink]
18 Aug 2018, 02:13



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Re: If m and n are the roots of the equation [#permalink]
18 Aug 2018, 04:46
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Appreciate the comments, Carcass. Sorry for being careless, and thank you for the clarification on the question.
However, I think you made a mistake there. If m=4 and n=2, then (m+n)(m−n) = (4+2) (42) = 12. I doesn't make a whole lot of difference though, because I guess we just established that this is not a wellthoughtout question.
Thanks!




Re: If m and n are the roots of the equation
[#permalink]
18 Aug 2018, 04:46





