Finding the rate of change

Rate of change is how much y moves for each 1 that x moves: the change in y divided by the change in x.

Take both rows of steps. x moves 3, 3, 3 — the same each time — and y moves −27, −27, −27. Both are steady, so there is one rate.

In one step, y moved −27 while x moved 3.

Now divide: −27 ÷ 3 = −9 — that is how far y moves for one x.

So the rate of change is −9: y moves −27 while x moves 3, and −27 ÷ 3 = −9.