Functions whose graphs resemble sets of stairsteps are known as step functions.
The most famous of the step functions is the greatest integer function, which is
denoted by:
[tex]f(x)=[x][/tex]
which graph is shown in the Figure below. As you can see from the graph:
[tex]if \ x=-1.8 \ then \ f(-1.8)=[-1.8]=-2[/tex]
Therefore:
[tex]f(-1.8)=-2[-1.8]+8=-2(-2)+8=\boxed{12}[/tex]
So the right answer is 12
