To begin with, let us look at a few definitions that will help
A relation is a function if each x-value is paired with exactly one y-value. A vertical line test on a graph can be used to determine whether a relation is a function.
If we use a graph to check, we will have
We can see that there is no overlapping of coordinates. The table satisfies the vertical line test.
Hence, it is a function
The domain and range of function is the set of all possible inputs and outputs of a function respectively. The domain and range of a function y = f(x) is given as domain= {x ,x∈R }, range= {f(x), x∈Domain}.
The domain of the function, D is given by

The range, R is given by
J because the x value is used more then once.
Answer:
it is algebraic expression
Answer:
The slope of line is 0 given points (2,8)(7,8)
Step-by-step explanation:
We need to find slope of line given points (2,8),(7,8)
The formula used to find slope of line is: 
We are given:

Finding slope using formula:

So, the slope of line is 0