Answer:
-1/4
Step-by-step explanation:
formula: y=mx+b
x+4y=16
x-4y+4y= 16-4y
x=16-4y
x-16=16-16-4y
x-16= -4y
(x-16)/-1=-4y/-1
-x+16=4y
(-x+16)/4=4y/4
-1/4x+4=y
this makes -1/4 your slope :) hope I explained well