Question

Which graph represents a function?

Answer 1

The last option is a function. Apply the vertical line test, which is seeing if the line has two points in the same downward line. Use the second option for example. If you put a line down, it would touch two spots on the graph at all times, so it is not a function.

Answer 2

Graph D represents a function

Explanation:

A function is a mathematical expression in which for each corresponding value of x or independent variable after applying the function rule we obtain one and only one y value or dependent variable value.

In graph A for x= -1 we obtain multiple values of y from 3 to -2 so is not a function.

In graph B for values of x>-2 we also obtain two values of y so its not a function.

In graph C for values of x<-1 we also obtain two values of y so its not a function.

In graph D for values for each x value we obtain one and only one value of so its a function

Ther vertical line test is a quick test to check if a graph is a function. If we draw a vertical line that crosses the graph in more than two points, the graph does not represent a function. The only case where we cannot do this is D so this is the function