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algebra senior
Problem
Both roots of the quadratic equation are prime numbers. The number of possible values of is
(A)
(B)
(C)
(D)
Solution
Consider a general quadratic with the coefficient of being and the roots being and . It can be factored as which is just . Thus, the sum of the roots is the negative of the coefficient of and the product is the constant term. (In general, this leads to Vieta's Formulas). We now have that the sum of the two roots is while the product is . Since both roots are primes, one must be , otherwise, the sum would be even. That means the other root is and the product must be . Hence, our answer is .
Final answer
B