Anything inside a square foot can be multiplied together. In this case, it forms :

So, B is the correct answer.
Technically, that expression can be further simplifyed, but that is not required on this question, so you're all good!
1, 3, 5, 7, 8, 11, 13, 15 is the answer.
Area of a Trapezoid can be defined by:
A =

just substitute given information

8.1 = .75(b₁ + 6.7)
8.1 = .75b₁ + 5.025
8.1 - 5.025 = .75b₁
3.075 = .75b₁

4.1 = b₁
the other base is equal to 4.1
Answer: = 8
Step-by-step explanation: Hope this help :D