find the slope using the slope formula of 12,5 and 9,8

The slope formula is given by:

m = (y2 - y1) / (x2 - x1)

Using the points (12, 5) and (9, 8):

m = (8 - 5) / (9 - 12)
= 3 / -3
= -1

Therefore, the slope is -1.