The set of values assigned to x in the equation y = x² is called the domain.
In mathematics, the domain of a function is the complete set of possible values of the independent variable. In this case, x can take any real number, so the domain of the function y = x² is all real numbers (often denoted as <code>(-∞, ∞)</code>).
Understanding the domain is crucial because it tells us what input values are acceptable for the function. In this specific equation, as we plug different values of x into the function, we can find the corresponding y values, which are part of the function’s range.