The function
[tex]f(x)=-2x+4[/tex]
Is a linear function, which means it is a straight line. To draw this graph you could find two points that belong to this lines, and draw a straight line that passes through those points. The easiest are the intercepts.
x-intercept:
[tex]0=-2x+4\Rightarrow x=2[/tex]
(2, 0)
y-intercept:
[tex]f(0)=4[/tex]
(0, 4)
The graph of this function looks like this:
