Answer:
40.90
Step-by-step explanation:
I do not know what pen is but if it is dollars then....
Answer:

Step-by-step explanation:
Use the square of a binomial theorem
= 
Now expand the given equation:

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The standard for is 2000+ 1200
Answer:
6 n + 6 b + 1
Step-by-step explanation:
Simplify the following:
11 b - 7 - 3 n + 8 - 5 b + 9 n
Grouping like terms, 11 b - 7 - 3 n + 8 - 5 b + 9 n = (9 n - 3 n) + (11 b - 5 b) + (8 - 7):
(9 n - 3 n) + (11 b - 5 b) + (8 - 7)
9 n - 3 n = 6 n:
6 n + (11 b - 5 b) + (8 - 7)
11 b - 5 b = 6 b:
6 n + 6 b + (8 - 7)
8 - 7 = 1:
Answer: 6 n + 6 b + 1