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Algebra

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 Joined: 25 Mar 2012 Post: 28
5 Apr 2012 17:14:55 IST
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If 4 distinct points of the curve y=2x^4+7x^3+3x-5 are collinear,then A.M of x-co ordinate ofthe 4 points is A)7/8 B)-7/8 C)3/4 D)-3/4

Scorching goIITian

Joined: 10 Feb 2012
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5 Apr 2012 19:00:09 IST
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Blazing goIITian

Joined: 21 Mar 2012
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5 Apr 2012 19:24:56 IST
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Ths eq. Has 4 rots whose sum is given by=-b/a here b=7 and a=2 so sum of 4 points wil be=-7/2 and its AM is -7/8

Scorching goIITian

Joined: 10 Feb 2012
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6 Apr 2012 13:14:13 IST
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@ Tarun Garg I don't think it's that way you get the solutionsuppose the given line is y=mx+c then for the point of intersection substitute for y in the given curve and now you will get the equation 2x^4+7x^3+3x-mx+-5-c=0 you have four roots here( And not directly saying from the first equation) Now four roots sum of the roots am.. Hence by four...Isn't it @Tarun Garb

Scorching goIITian

Joined: 10 Feb 2012
Posts: 262
6 Apr 2012 13:14:15 IST
0 people liked this

@ Tarun Garg I don't think it's that way you get the solutionsuppose the given line is y=mx+c then for the point of intersection substitute for y in the given curve and now you will get the equation 2x^4+7x^3+3x-mx+-5-c=0 you have four roots here( And not directly saying from the first equation) Now four roots sum of the roots am.. Hence by four...Isn't it @Tarun Garg

Scorching goIITian

Joined: 10 Feb 2012
Posts: 262
6 Apr 2012 13:14:15 IST
0 people liked this

@ Tarun Garg I don't think it's that way you get the solutionsuppose the given line is y=mx+c then for the point of intersection substitute for y in the given curve and now you will get the equation 2x^4+7x^3+3x-mx+-5-c=0 you have four roots here( And not directly saying from the first equation) Now four roots sum of the roots am.. Hence by four...Isn't it @Tarun Garg

Scorching goIITian

Joined: 10 Feb 2012
Posts: 262
6 Apr 2012 13:14:16 IST
0 people liked this

@ Tarun Garg I don't think it's that way you get the solutionsuppose the given line is y=mx+c then for the point of intersection substitute for y in the given curve and now you will get the equation 2x^4+7x^3+3x-mx+-5-c=0 you have four roots here( And not directly saying from the first equation) Now four roots sum of the roots am.. Hence by four...Isn't it @Tarun Garg

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