Question

What is the domain and range of these functions y=-0.7x+1.9 and y=0.7x+1.9

Answer 1

I don't get why the answers are: Left half: Domain:
−2.7≤x≤0
range:
0≤y≤1.9
Right half: Domain:
0≤x≤2.7
range:
0≤y≤1.9

Answer 2

I don't get the answers you are seeing either.
There is nothing that would lead to any type of restriction to the domain of either of the functions. Therefore the domains of both functions are the real numbers.
Similarly, the ranges for both functions are also the real numbers.

Answer 3

Both functions represent equations of a line. Lines are infinite and thus by definition will represent all values of x and all values of y.