Answer:
If d is zero, both roots are rational and equal.
Step-by-step explanation:
Quadratic Equations
The standard representation of a quadratic function is:
[tex]f(x)=ax^2+bx+c[/tex]
where a,b, and c are constants.
Solving with the quadratic formula:
[tex]\displaystyle x=\frac{-b\pm \sqrt{b^2-4ac}}{2a}[/tex]
The discriminant is defined as:
[tex]d=b^2-4ac[/tex]
The sign of the discriminant defines the nature of the roots of the quadratic equation as follows: