Answer
The graphs that represent functions which have an inverse are (b) and (d).
Work Step by Step
By the use of the horizontal line test we can determine whether the function has an inverse or not. If the horizontal line cuts the graph at a single point, the function is invertible.
In the first graph:
The graph consists of a horizontal line that cuts the graph into two points. Thus, the graph of the function does not have an inverse.
In the second graph:
The graph does not have any horizontal line that cuts the graph of the function more than once. Thus, the graph has an inverse function.
In the third graph:
In the graph, the horizontal line passes through the graph of the function more than once. Thus, the function of the graph does not have an inverse.
In the fourth graph:
There is no horizontal line that passes through the graph of the function more than once. Thus, the graph of the function has an inverse.
Hence, the graphs (b) and (d) represent functions having an inverse.
