Multiple choice

Which of the following equations has equal roots?

  1. x2 + 4x + 4 = 0

  2. x2 + 4x - 4 = 0
    • x2 + 4x + 4 = 0

  4. x2 + 6x + 6 = 0
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A Correct answer
Explanation

A quadratic equation ax^2 + bx + c = 0 has equal roots if the discriminant D = b^2 - 4ac = 0. For option A: 4^2 - 4(1)(4) = 16 - 16 = 0. This satisfies the condition.

AI explanation

A quadratic equation has equal roots if its discriminant, D = b2 - 4ac, is equal to zero. For the equation x2 + 4x + 4 = 0, the coefficients are a = 1, b = 4 and c = 4. Calculating the discriminant gives D = 42 - 4(1)(4) = 16 - 16 = 0, confirming it has equal roots.

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