SOLUTION: pls help me to answer: if the sum of the reciprocals of the roots of the equation 3x^2+7x+k is -7/3, what is <s>K</s> k?

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Question 890739: pls help me to answer: if the sum of the reciprocals of the roots of the equation
3x^2+7x+k is -7/3, what is K k?
Answer by josgarithmetic(39618) About Me  (Show Source):
You can put this solution on YOUR website!
Sum of reciprocals of roots of 3x^2+7x+k is -7/3. Find k.

x=%28-7%2B-+sqrt%2849-4%2A3%2Ak%29%29%2F6
x=%28-7-sqrt%2849-12k%29%29%2F6 or x=%28-7%2Bsqrt%2849-12k%29%29%2F6

-6%2F%287%2Bsqrt%2849-12k%29%29%2B6%2F%28-7%2Bsqrt%2849-12k%29%29=-7%2F3 according to specification in question.
-6%2F%28sqrt%2849-12k%29%2B7%29%2B6%2F%28sqrt%2849-12k%29-7%29=-7%2F3
Multiply left and right by lowest common denominator...
-6%2A3%28sqrt%2849-12k%29-7%29%2B6%2A3%28sqrt%2849-12k%29%2B7%29=-7%28%2849-12k%29-49%29
-18sqrt%2849-12k%29%2B18%2A7%2B18sqrt%2849-12k%29%2B18%2A7=7%2A12k
2%2A18%2A7=7%2A12k
2%2A18=12k
2%2A6=4k
highlight%28highlight%28k=3%29%29