Ex.( a basic example)
f(x)=x^2 or y=x^2;
this equation is in quadratic form obviously its function is parabolic,
plugging in any real number for x and you will find the value of y, and place this in a table for you to plot or sketch in the graph, after sketching the points u can easily identify those numbers belong to domain and range, as well as by seeing the table.
if you have observed the above figures, the range(y) can be identified ,all real numbers except less than o and the domain (x) are all real numbers.
Now, if you plot this in a graph, the sketch is a parabola (facing upward) excluding negative in the y axis..