# What is the domain and range of y=x^2?

The domain is the set of all allowed $x$ values. Although it is not 100% certain from the graph, it is clear from the equation, that for any number you put in for $x$ you will get one and only one value for $y$. The domain is all real numbers . (The interval $\left(- \infty , \infty\right)$)
The range is the set of all $y$ value the graph actually includes. Looking at the graph (and thinking about ${x}^{2}$, it becomes clear that $y$ will never have a negative value.
It is not 100% certain from the graph, but every number that is NOT negative will be used as a $y$ value. The range is $\left[0 , \infty\right)$