[tex]\\ \sf\longmapsto f(x)+-2^x[/tex]
Graph attached
How to find domain and range from co-ordinate pairs?
Now look at the graph
Here domain can be any real number .
[tex]\\ \sf\longmapsto D_f\in R[/tex]
And
Range starts from 0 and infinite in negative y direction.
[tex]\\ \sf\longmapsto R_f\in (\infty,0][/tex]