We have

so this is indeed a difference of squares. Factorizing would give

making the answer D.
We can further factor the first term here and write

but that's clearly out of the scope of this question.
Answer:
13
Step-by-step explanation:
Start with adding the feet: 6+4+5=15
then add the inches: 5+6+7=18
18 inches= 1 foot and 6 inches
So its 16 feet and 6 inches
Idk but it can't be 10 or 9.7 bc a triangle's hypotenuse is always longer than its legs