Well according to the slope intercept equation.
Y = mx +/- b
The slope is the value m
The y intercept is b
To graph the function, one sure way to do it is simply make a table of values picking any x values that fall within the graph space, and finding out the resulting y values and using the points to graph.
For instance for the first graph, if x = 0, y = 5, that is one possible point. Keep on choosing x values to graph.