In the formula of a quadratic equation, the part below the square root is called the discriminant.

The value of the discriminant shows directly how many solutions (roots) to the quadratic equation there are. When the discriminant is positive, the equation has two solutions. When the discriminant is zero, there is one solution and if the discriminant is negative there are no solutions to the equation at all.

Example 1

Find out how many roots the equation below has.

The discriminant is positive, so there are 2 roots

The discriminant is denoted by the letter D

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