What is the domain of quadratic functions?

Hint: From the given question we have been asked to find the domain of a quadratic function. To solve this question we will use the definition of domain from the concept of functions. We will explain the domain definition and then we will correlate this to our quadratic equation and then we will find the required solution to the given question. So, we proceed with our solution as follows.

Complete step-by-step answer:
Generally in mathematics the domain for any kind of function is the set of all input values where the function is valid or defined.
So, here we have to find out where the quadratic functions are valid and all those input values to the quadratic equations will be its domain.
The general form of a quadratic function is \[ y=a{{x}^{2}}+bx+c\].
The quadratic functions will result in a parabola because the parabolas will expand infinitely the domain will be \[ \left( -\infty ,\infty \right)\].
Therefore, we can say that the domain of a quadratic function in standard form is always all real numbers, meaning we can substitute any real number for x.

Note: Students must have good knowledge in the concepts of functions and quadratic equations. We must know the definition and applications of the domain term in functions. We must know that the quadratic functions will result in a parabola to solve this question.