Math Is Fun Forum

soha

Real Member

Registered: 2006-07-07

Posts: 2,530

value of k

If one root of 5x2 + 13x + k = 0 is equal to the reciprocal of the other, then the value of ‘k’ is
A) 0 B) – 6 C) 5 D) 6

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- David O. McKay

ZHero

Real Member

Registered: 2008-06-08

Posts: 1,889

Re: value of k

C)

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soha

Real Member

Registered: 2006-07-07

Posts: 2,530

Re: value of k

How did you get ??

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"Let us realize that: the privilege to work is a gift, the power to work is a blessing, the love of work is success!"
- David O. McKay

soha

Real Member

Registered: 2006-07-07

Posts: 2,530

Re: value of k

How did you get c

Please, someone explain

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"Let us realize that: the privilege to work is a gift, the power to work is a blessing, the love of work is success!"
- David O. McKay

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: value of k

Hi soha;

You can rule A out right away, can you see why?

What are the roots of the quadratic when k = 6 and when k = - 6?

Now you will see that the answer has to be C.

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

ZHero

Real Member

Registered: 2008-06-08

Posts: 1,889

Re: value of k

now put the values of c and a and you'll get....

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If two or more thoughts intersect, there has to be a point!