Answer
Refer to Graph I and by way of Vertical Line Test, it is a function.
The domain is $(–\infty, \infty)$.
The range is $[0, \infty)$.
Work Step by Step
Refer to Graph I and by way of Vertical Line Test,
it is a function because each vertical line drawn will not intersect the curve on the graph in more than one point.
And, for any value of x, there will be exactly one corresponding value for y, so the equation $y = x^2$ defines a function.
The x-values of the points on the curve will include all the real numbers between $–\infty$ and $\infty$. The domain is $(–\infty, \infty)$.
Because there is a minimum y-value of 0 when x = 0 and all the y-value will be a non-negative number, the y-values of the points on the curve will include all the real numbers from $0$ to $\infty$. The range is $[0, \infty)$.
