Match the graphs below with the equations following. (Note that the and scales may be unequal.)
I. Graph of a line with a zero y-intercept and negative slope.II. Graph of a line with a positive y-intercept and positive slope.III. Graph of a line with a zero y-intercept and positive slope.
IV. Graph of a line with a positive y-intercept and negative slope.V. Graph of a line with a negative y-intercept and positive slope.VI. Graph of a line with a negative y-intercept and negative slope.

(For each, enter the correct roman numeral, e.g., II, without any punctuation.)

(a) : (b) :
(c) : (d) :
(e) : (f) :