Answer:
Step-by-step explanation:
You can use this by multiplying what needs to be multiplied and eliminate what isn't needed.
Answer : 81 because it is the only one that is not a multiple of 4
Step-by-step explanation:
Answer: The length of JF = 16 units.
Step-by-step explanation:
Given: In triangle DEF, segment DJ is a perpendicular bisector of side EF.
i.e. DJ is perpendicular to EF and DJ divides EF into two equal parts EJ and JF. [The perpendicular bisector is a line that is perpendicular to a line segment and splits it into two congruent segments.]
If EJ is 3y-8 and JF is 7y-40.
Then, 
![\Rightarrow\ 7y-3y=40-8\\\\\Rightarrow\ 4y=32\\\\\Rightarrow\ y=8 \text{ [Divide both sides by 4]}](https://tex.z-dn.net/?f=%5CRightarrow%5C%207y-3y%3D40-8%5C%5C%5C%5C%5CRightarrow%5C%204y%3D32%5C%5C%5C%5C%5CRightarrow%5C%20y%3D8%20%5Ctext%7B%20%5BDivide%20both%20sides%20by%204%5D%7D)
JF= 7(8)-40 =56-40= 16 units
Hence, the length of JF = 16 units.
Its okay, the first half is completely irrelevant. All that matters is x and y. y = 16, because y is how much space the books take up. x = 8, since x is the number of books. All you have to find is the proportions. It is most likely talking about the proportions of the books, so you would need to find the length if each book. You know they will all be the same because it was previously mentioned each book is the same size. So the equation is:

Since 16/8 is 2, you would get 2in/book.
Hope that helps!
Answer:
x = 7.348
Step-by-step explanation:
I don't really know how to explain this over a computer, but it is correct. Answer credit of Omnicalculator.
Hope that this helps!