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Number and Type of Solutions of a Quadratic Equation Based on the Discriminant

The value of the discriminant, b24acb^2 - 4ac, reveals the number and type of solutions for a quadratic equation ax2+bx+c=0ax^2 + bx + c = 0 (where a0a \neq 0), without requiring the equation to be fully solved:

  • If b24ac>0b^2 - 4ac > 0 (positive discriminant), the equation has two real solutions.
  • If b24ac=0b^2 - 4ac = 0 (zero discriminant), the equation has one real solution.
  • If b24ac<0b^2 - 4ac < 0 (negative discriminant), the equation has two complex solutions (meaning it has no real solutions).
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Updated 2026-05-18

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