Answer:
Function:
- 1, vertical line
- 2, two lines
- 4, bent line
- 5, line
Not a function:
- 3, circle
- 6, the last bent curve
Explanation:
In order to determine whether a graph is a graph of a function or not, you simply look for the ones that do not give two or more y for every x. In other words, imagine a vertical line going from left to right and ask yourself: how many times does the line cross the graph? If you find even a single x which gives two y, the graph is not a function. For examples take a look at the sketches i drew ;)