ANSWER and EXPLANATION
5. A line only has a slope of 0 if that line is a horizontal line. Hence, we have to identify the horizontal lines on the boat.
The horizontal lines on the boat are:

Those are the lines with a slope of 0.
6. A line only has an undefined slope if that line is a vertical line. Hence, we have to identify the vertical lines on the boat.
The vertical lines on the boat are:

Those are the lines with an undefined slope.
7. To find the slope of ED, apply the formula for the slope of a line:

where (x1, y1) and (x2, y2) are two points that lie on the line.
The points (x1, y1) and (x2, y2) are(-11, 4) and (-10, 5). Hence, the slope of the line is:

That is the answer.