For how many integer values of does the equation have two distinct integer roots?
Answer and explanation
Correct answer: A.
- Step 1: If the roots are the integers and then and , with .
- Step 2: The unordered pairs with product and are and their negatives .
- Step 3: These give : six different values of .
Answer
.
Why not the others: counts only the positive pairs; and lose one or two of the negative pairs; counts ordered pairs (each swap gives the same ).
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