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Difficulty: 5/102025 IOQM 2025 (Q15)

If the roots of the quadratic equation are consecutive integers, find the value of .

Options:

  • A.

    3

  • 1

  • C.

    2

  • D.

    4

Guide / Hint

Hint 1: Let the roots be and . If they are consecutive, then , which means .

Hint 2: Use Vieta's formulas: the sum of the roots is and the product of the roots is .

Hint 3: Recall the algebraic identity: . Substitute the values into this identity.

Solution

Step 1: Let the roots of the quadratic equation be and . Since they are consecutive integers, we have:

Step 2: By Vieta's formulas, the sum and product of the roots are:

Step 3: Express the squared difference in terms of the sum and product:

Step 4: Substitute the values from Vieta's formulas and step 1:

So the value of is . This is the discriminant of the quadratic equation.

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