Answer:
If d is zero, both roots are rational and equal.
Explanation:
Quadratic Equations
The standard representation of a quadratic function is:
![f(x)=ax^2+bx+c](https://img.qammunity.org/2021/formulas/mathematics/middle-school/hj2cyo9lipsf2imfe8tb04vftddbodxbcu.png)
where a,b, and c are constants.
Solving with the quadratic formula:
![\displaystyle x=(-b\pm √(b^2-4ac))/(2a)](https://img.qammunity.org/2021/formulas/mathematics/middle-school/s3age13u1k5t2be3r2834z0ijj7y78cct5.png)
The discriminant is defined as:
![d=b^2-4ac](https://img.qammunity.org/2021/formulas/mathematics/college/mbvgqu5rf5t2qtahdx0updatl13ckdpglo.png)
The sign of the discriminant defines the nature of the roots of the quadratic equation as follows:
- If d is positive, both roots are real and different
- If d is negative, both roots are imaginary and conjugate
- If d is zero, both roots are rational and equal.