Answer
a) Yes
b) Yes
Check attached files
Work Step by Step
The horizontal line test confirms that the functions are one-one.
a) is pretty straightforward: the graph shows that the function is one-one: no horizontal line can be found such that it intersects the graph at two points.
b) We see that the only point of intersection on the x-axis (when x = 0) is at y = 1 (point: 1,0).