Very simple:
As the sides that subtend the angle x are of equal lengths and are joined to form a triangle, we know the only other angle (the blank one) is going to also be 56° and since angles in a triangle always add up to 180°, we just have to do:
180 - (2 × 56) = 68°

The answer is the first one.
Hope this helps. - M
Answer:
find below
Step-by-step explanation:
5(x-7)=20
5x-35=20
5x=55
x=11
Part A
.. (480 books)/(5 cartons) = 480/5 books/carton = 96 books/carton
Part B
.. (7440 dollars)/(480 books) = 7440/480 dollars/book = $15.50 for 1 book
Part C
.. (2 minutes)/(48 books) * (200 books) = 400/48 minutes
.. = 8 minutes 20 seconds
Part D
In 9 minutes, the worker unpacked
.. (48 books)/(2 minutes)*(9 minutes) = 216 books
In 9 minutes, the manager upacked
.. (54 books)/(3 minutes)*(9 minutes) = 162 books
We note that 216 -162 = 54.
The worker unpacked 54 more books in 9 minutes than the manager did.