Pls which formulas are these I just justed these and I don't know the topic and where and when to apply the formula

Here are the formulas and their explanations:

1. $x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}$ This is the quadratic formula.

   • Topic: It is used in algebra to solve quadratic equations.
   • Application: You apply this formula to find the values of $x$ (the roots or solutions) for any quadratic equation written in the standard form $ax^2 + bx + c = 0$, where $a$, $b$, and $c$ are coefficients and $a \neq 0$.

2. $D = b^2 - 4ac$ This is the discriminant of a quadratic equation.

   • Topic: It is also part of algebra and relates to quadratic equations.
   • Application: You use the discriminant to determine the nature of the roots (solutions) of a quadratic equation $ax^2 + bx + c = 0$ without solving the entire equation.
     • If $D > 0$, there are two distinct real roots.
     • If $D = 0$, there is one real root (a repeated root).
     • If $D < 0$, there are two complex conjugate roots (no real roots).