Final answer:
To confirm if a graph represents a non-linear function, check if it passes the vertical line test to ensure it's a function, and then verify if the graph is not a straight line, indicating non-linearity. Linear functions have the form y = mx + b with a constant slope, while non-linear functions have curves or varying slopes.
Step-by-step explanation:
To determine if a graph is a non-linear function, we need to first confirm that it is a function. One way to do this is by checking to see if each x-value is paired with exactly one y-value, which is known as the vertical line test. However, the uniqueness of y-values is not a proper test for a function, as multiple x-values can be associated with the same y-value in many functions.
A linear function can be identified by its graph, which is a straight line and can be represented by the equation y = mx + b, where m is the slope and b is the y-intercept. In contrast, non-linear functions will have graphs that are not straight lines; they could have curves, peaks, and different slopes at various points.
For example, a linear equation such as y = 2x + 1 will produce a straight line when plotted on a graph, while a non-linear function such as y = x^2 will show a parabolic curve.