ANSWER
a. d+4
b. 4d+16
EXPLANATION
The area of the square coaster is represented by:

We split the middle term to obtain,

We factor by grouping to get,


Since area of a square is l² , it means the side length of the square is

b) The perimeter of a square is given by

We substitute the length in terms of d, to obtain;

Or

5 brownies and 15 cookies.
Working
4 plates —> 2B + 6C
1 plate —> 2/4B + 6/4C
10 plates —> 5B + 15C
Answer: 9
x
3
(
5
x
+
8
)
Step-by-step explanation:
Factor 9
x
3 out of 45
x
4
+
72x
3
.