Answer: The slope is -1
Step-by-step explanation:
When you are given a line on a graph all you need to do is pick two points on the line and calculate the change over both the x and y-axis.
Pick both points to be at a position on the line that is easy to read. IE the intersection between two grid lines. For this problem lets go with the first point at (0,1) and the second point at (1,0).
Now we want to calculate the change in rise (the y-component) and divide by the change in the run (the x-component). Point 1 has a y-component of 1 and point 2 has a y-component of 0.
1 - 0 = 1 = rise
Point 1 has an x-component of 0 and point 2 has an x-component of 1.
0 - 1 = -1 = run
rise/run = 1/-1
Slope = -1