Answer:
-1
Explanation:
As given in the picture you provided, the slope is defined as:
and the reason for this, is because in subtracting y_1 from y_2, you're finding how much the y-value changed, or in other words, the rise. When subtracting x_1 from x_2 you're finding how much the x-value changed, or in other words the run. Another way of expressing the slope that you may have seen is:
which is essentially what this slope formula is doing.
One thing to note is that what I assign to (x_1, y_1) and (x_2, y_1) doesn't matter, as long as they're two different points on the linear line.
So let's just say that:
and that:
Now plugging these values into the equation we get:
So the slope is -1