What type of roots the equation has can be shown by the discriminant. The discriminant for a quadratic equation \(a{x^2} + bx + c = 0\) is \({b^2} - 4ac\). And the types of root the equation has ...

Maybe your high school teacher didn’t want to deal with the issue of what happens when (b 2 - 4ac) – the expression under the square root in the quadratic formula – is negative.