The answer is -3/4 and y-intercept is 3 because another way is of slope is rise over run. Since it is negative 3, you go down three and since the run is 4, you go to the right 4 times to finally hit a perfect point in the graph.
For the y-intercept, look at the graph, and find the point of intersection of the line and the y-axis. You will see that the line and the y-axis intersect at 3. The y-intercept is 3.
To find the slope, you need to find two points that are easy to read on the graph. You must go from one point to the other, but you can only move vertically and horizontally along grid lines. Look at (0, 3) and (4, 0). Slope is rise over run. Rise is up and down. Run is left and right. Start at (0, 3), the y-intercept. To go from that point to (4, 0), you go 3 units down. Down is negative, so the run is -3. Then you are at the origin, (0, 0). To go to (4, 0), now you go 4 units to the right. That is a run of 4. The rise is -3, and the run is 4.
Here are some very good video that explain how. very short and easy too. http://virtualnerd.com/pre-algebra/linear-functions-graphing/rate-of-change-slope/finding-slope/slop... math antics on youtube is great for help too
