Pls i give !
which is an example of the commutative property?
a.
–13 + 27 = 27 + (–13)
b.
–21 + (11 + 13) = (–21 + 11) + 13
c.
4(–3 + 5) = 4(–3) + 4 ∙ 5
d.
–(–8 + 3) = 8 + (–3)

Abouncy ball is dropped such that the height of its first bounce is 5.5 feet and each successive bounce is 64% of the previous bounce's height. what would be the height of the 7th bounce of the ball? round to the nearest tenth (if necessary).

The head librarian at the library of congress has asked her assistant for an interval estimate of the mean number of books checked out each day. the assistant provides the following interval estimate: from 740 to 920 books per day. what is an efficient, unbiased point estimate of the number of books checked out each day at the library of congress?

Given a: b and b: c, find a: b: c. write the ratio in simplest form. a: b=6: 10 and b: c=21: 33