Question 37681
This is a called a linear function. 
The standard form of this type of function is {{{y=mx+b}}}
m represents the slope or {{{rise/run}}}
b represents the y-intercept, or when x=0

{{{.3}}} can also be written as {{{3/10}}}
{{{y=(3/10)x}}}
{{{graph(400,400,-10,10,-10,10,(3/10)x)}}}

Domain is infinity becuase the line continues on forever.
Range is also infinity because the line continues on forever.

Hope this helps!