+2,+2,+2,-2,-2,-2,+2,+2,+2 etc
Answer:

Step-by-step explanation:
From the question we are told that:
Length of pool 
width of pool 
Width of brick-walk way
Generally the equation for Area of the pool
is mathematically given by

Generally the equation for Area of the pool with its walkway
is mathematically given by

Where

Therefore

Generally the equation for pool's walkway
is mathematically given by


Answer:
3a. 84
3b. 150
Step-by-step explanation:
(3*7)+(3*21)
what is 3*7? it's 21
what is 3*21? it's 63
so 21 + 63 is the answer to the first question :D
10*(8+7)
8+7 first cause it's in parentheses
15
10*15 is equal to 150
The answer is d)3 because each number gets multiplied by 3 to qual the next number