What is the domain and range of ##y=2x-6##?

The domain and range is both all real numbers ##RR##

This is a linear function so its graph is a straight line and so all x values are allowed as inputs (domain) and all y values are allowed as outputs (range). The function is unbounded.

The graph verifies this.

graph{2x-6 [-9.91, 15.4, -6.53, 6.13]}