Answer:
Step-by-step explanation:
The easiest way to understand a slope of - 1 is to graph something with a slope of - 1
y = - x has a slope of - 1.
You need something to compare it to so I'll graph both y = - x and y = x
red: y = -1x
blue:y = x
The difference is in the direction that they go. They are at right angles to each other.
y = x goes from lower left to upper right.
y = -x goes from lower right to upper left.
Even a slightly more complicated graph like
y = x + 4 does exactly the same thing. It goes from lower left to upper right.
