Answer
They are family of parallel lines with different intercepts on y-axis
Work Step by Step
Family of lines $2x - y = C$ are parallel line
Rearranging we get $y = 2x-C$
And lines then become
For C = 2, $y = 2x-2$, Line has negative y intercept
For C = 0, $y = 2x$, Line passes through origin and has positive slope
For C = -4, $y = 2x+4$, Line has positive y intercept
