Question 1:
The domain of a function is defined as the input values of the function. Conventionally, they are the values of the x-coordinates of the function.
Therefore, the domain of the given function would be the x-values of the given points.
This means that:
domain is : {0 , 3 , 5 , 8} ................> option B
Question 2:
For a relation to be a function, each x-value should have one and only one corresponding y-value. Otherwise, it won't be a function.
In the given, we can note that x = 0.3 has two y-values (0.6 and 0.7), therefore, this relation is not a function ...........> option B
Hope this helps :)