Answer:
The function  is one-to-one function ⇒ 1st
 is one-to-one function ⇒ 1st
The function  is one-to-one function ⇒ 2nd
 is one-to-one function ⇒ 2nd
The function  is one-to-one function ⇒ 4th
 is one-to-one function ⇒ 4th
Step-by-step explanation:
* Lets explain how to solve this problem
- One to one function is the function that has no reputation in the value
  of the y-coordinates for every corresponding x-coordinates
- That means when you draw a horizontal line at any value of y, then
   the horizontal line intersects the graph of the function at one point
   only
- So to solve the problem look to the attached figures
# The red graph of the function  ⇒1st graph
 ⇒1st graph
- In this graph if we draw a horizontal line at any value of y it will
  intersect the graph at only one point 
- Take care there is a horizontal asymptote at y= 1/3, that means 
   there is no value of x at y = 1/3
∴ The function  is one-to-one function
 is one-to-one function
# The blue graph of the function  ⇒2nd graph
 ⇒2nd graph
- In this graph if we draw a horizontal line at any value of y it will
  intersect the graph at only one point 
∴ The function  is one-to-one function
 is one-to-one function
# The green graph of the function  ⇒3rd graph
 ⇒3rd graph
- In this graph if we draw a horizontal line at any value of y it will
  intersect the graph at only one point 
∴ The function  is one-to-one function
 is one-to-one function
# The purple graph of the function  ⇒5th graph
 ⇒5th graph
- In this graph if we draw a horizontal line at any value of y it will
  intersect the graph at more than one point 
∴ The function  is not one-to-one function
 is not one-to-one function
# The black graph of the function  ⇒4th graph
 ⇒4th graph
- In this graph if we draw a horizontal line at any value of y it will
  intersect the graph at more than one point 
∴ The function  is not one-to-one function
 is not one-to-one function
* The answers are 1st , 2nd and 4th functions