I can tell you the steps to graph them.
The easiest one is d(t) = 4t; this graph has a slope of 4 and a y-intercept of 0.
The first point you will plot is a point at the origin. From this point, count up four and then right 1 and plot another point. Count up 4 and right 1 again and plot a point. Now use a straight edge and draw a line through the points. Be sure to put arrows on the end of the line.
d(t) = 3t + 1.5; this graph has a slope of 3 and a y-intercept of 1.5. The first point to plot is a point on the y-axis at 1.5 (in the middle of 1 and 2). from this point count up 3 and then right 1 and plot a point, do this again two more times and then draw another line. Remember these points will be between the lines since we are counting on the halves.
I hope this helped.