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Math Revolution GMAT Instructor
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If 2 roots of an equation x^23x3=0 are m and n, what is the value of
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21 Oct 2016, 08:31
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If 2 roots of an equation x^23x3=0 are m and n, what is the value of m^2+n^2? A. 10 B. 12 C. 15 D. 24 E. 25 * A solution will be posted in two days.
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If 2 roots of an equation x^23x3=0 are m and n, what is the value of
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21 Oct 2016, 08:52
m = x + y n= x  y Where x= b/2a y= (sqrt(b^2  4ac))/2a m^2+n^2 = 2(x^2 + y^2) = 2(9/4 + 21/4) =15 C Sent from my iPhone using GMAT Club Forum mobile app



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Re: If 2 roots of an equation x^23x3=0 are m and n, what is the value of
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21 Oct 2016, 09:00
MathRevolution wrote: If 2 roots of an equation x^23x3 = 0 are m and n, what is the value of m^2+n^2?
A. 10 B. 12 C. 15 D. 24 E. 25
* A solution will be posted in two days. With acegmat123That's the perfect and easiest way of solving this question
With (C) hence... PS : Good question MathRevolution ...
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Re: If 2 roots of an equation x^23x3=0 are m and n, what is the value of
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26 Oct 2016, 02:56
==>From x^23x3=(xm)(xn)=x^2(m+n)x+mn, you get m+n=3 and mn=3. Then you get m^2+n^2=(m+n)^22mn=3^22*(3)=15. The answer is C. Answer: C
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Re: If 2 roots of an equation x^23x3=0 are m and n, what is the value of
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30 Oct 2016, 09:08
Can someone post a step by step solution pls...Kudos for this



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Re: If 2 roots of an equation x^23x3=0 are m and n, what is the value of
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04 Nov 2016, 01:31
AK125 wrote: Can someone post a step by step solution pls...Kudos for this Hi AK125, x^23x3=(xm)(xn)=x^2(m+n)x+mn so, mn=3 and mn=3 Thank you.
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Re: If 2 roots of an equation x^23x3=0 are m and n, what is the value of
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04 Nov 2016, 16:08
It is not clear enough. I miss some step above. please any help ?



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Re: If 2 roots of an equation x^23x3=0 are m and n, what is the value of
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05 Nov 2016, 03:11
MathRevolution wrote: ==>From x^23x3=(xm)(xn)=x^2(m+n)x+mn, you get m+n=3 and mn=3. Then you get m^2+n^2=(m+n)^22mn=3^22*(3)=15. The answer is C.
Answer: C I don't understand when you solve for (m^2 + n^2) and use (m+n)^2  2mn in its place Posted from my mobile device



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Re: If 2 roots of an equation x^23x3=0 are m and n, what is the value of
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08 Nov 2016, 04:01
gillyelephant wrote: MathRevolution wrote: ==>From x^23x3=(xm)(xn)=x^2(m+n)x+mn, you get m+n=3 and mn=3. Then you get m^2+n^2=(m+n)^22mn=3^22*(3)=15. The answer is C.
Answer: C I don't understand when you solve for (m^2 + n^2) and use (m+n)^2  2mn in its place Posted from my mobile device We do know m+n which equals 3. And we know mn which is 3. If we square (m+n) > ( m+n)^2 = m^2 + 2 mn + n^2 Plug in what we do know (green): (3)^2 = m^2 + 2(3) + n^2 > 9 = m^2  6 + n^2 > 15 = m^2 + n^2Hope its clear!



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Re: If 2 roots of an equation x^23x3=0 are m and n, what is the value of
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Re: If 2 roots of an equation x^23x3=0 are m and n, what is the value of
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