Resolve "Homework exercises 4.3"

Instructions

If you have finished (i.e. added solution/reviewed solution) an exercise please check the checkbox of the associated exercise:

Creating solution

• Exercise 1 (c)
• Exercise 2 (c)
• Exercise 3 (c)
• Exercise 4 (c)

Reviewing solution

• Exercise 1 (r)
• Exercise 2 (r)
• Exercise 3 (r)
• Exercise 4 (r)

Closes #16