The answer is: 
The explanation is shown below:
1- You have the following expression given in the exercise:

2- When you multiply signs, you obtain:

3. Now, you must add like terms, as following:

4. Therefore, you have that the expression simplified is:

Answer: side
Step-by-step explanation:
New length = 30x110% = 33cm
new width = 20x105% = 21cm
original perimeter = 30x2 + 20x2
= 60 + 40 = 100
new perimeter = 33x2 + 21x2
= 66 + 42 = 108
increase in perimeter = 108-100 = 8
percentage increase = 8/100 x 100% = 8%
Answer:
A = ...-5π ,-4π ,-3π, -2π, -π, 0, π, 2π, 3π, 4π, 5π....
A = {x ∈ N, πx}