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If two (positive) prime numbers are roots of the equation x^2-12x+k=0, what is the value of k?

 

THXXX

 Oct 4, 2019
 #1
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x^2 - 12x + k  = 0

 

By Vieta

 

The sum of the roots  =  -(-12) /1  =  12 / 1  =  12

 

The only two positive primes that sum to  12   are   5  and 7

 

So  we have that

 

(x - 7) ( x - 5)  =  0

 

x^2 - 7x - 5x  + 35  = 0

 

x^2 - 12x  +  35  = 0

 

So.....k = 35

 

cool cool cool

 Oct 4, 2019

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