
Step-by-step explanation
the domain refers to the set of possible input values, the domain of a graph consists of all the input values shown on the x-axis. The range is the set of possible output values, which are shown on the y-axis.
the function given are lines, in the form

so, when the values of its range decrease as the values in its domain increase
in other words
when x increase , y decrease, it is a negative slope, then

I hope this helps you