Multiple choice

Which of the following quadratic equations has discriminant 0?

  1. x2 + 4x + 2 = 0

  2. x2 + 4x + 4 = 0

  3. 2x2 + 4x – 2 = 0

  4. 2x2 – 4x – 2 = 0
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The discriminant of ax^2 + bx + c = 0 is b^2 - 4ac. For x^2 + 4x + 4 = 0, a=1, b=4, c=4. Discriminant = 4^2 - 4(1)(4) = 16 - 16 = 0.

AI explanation

The discriminant of a quadratic equation is given by the formula D = b^2 - 4ac. Calculate the discriminant for the equation x^2 + 4x + 4 = 0 by substituting a = 1, b = 4 and c = 4 to get D = 4^2 - 4(1)(4). Simplifying this gives D = 16 - 16 = 0, so the discriminant is 0.

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