Answer:
-2
Step-by-step explanation:
the line that passes trough (4, 7) and (8, 9) has the slope
m= (y2-y1)/ (x2-x1) = 7-9 / 4-8 = -2/ -4 = 1/2
perpendicular lines have their slope negative reciprocal
m= -2 is the slope of the perpendicular line that goes trough the given points
