8r and 4r are like terms since they both have an r
also 3s and -3s are also like terms because of the s
Answer:

Step-by-step explanation:
Let x be the number of minutes she can continue, since she's already 20 feet below the ocean surface and is diving at the rate of 20 ft/minute, her depth with respect to x would be
20 + 20x
But she doesn't want to reach more than 100 feet below the surface

Answer:
c:84
Step-by-step explanation:
set your equasion to 9/7 = 108/x .solve the equasion and you get 84 for x
Answer:
b
Step-by-step explanation:
This is the answer I hope this will help you