if one customer shows up, and she buys one song, that's $1.29, if she doesn't buy anymore, then that's the charge.
the first song is always at a full price, and after that, to encourage buying, the next ones are just 99 cents, let's see how it goes after a few songs purchases.
1 song.........................$1.29
2 songs.......................$1.29 + 0.99(2)
3 songs.......................$1.29 + 0.99(3)
4 songs.......................$1.29 + 0.99(4)
c songs.......................$1.29 + 0.99(c)
s(c) = 1.29 + 0.99c.
X=33 and Y= 57
Step by step explanation if you see the right angle at 57 degrees it part of x so x plus 57 is 90 and 90 minus 57 is 33 so x is 33 and x and y also form a right angle so x plus y should equal 90 and 90 minus 33 is 7 so that’s Y
Answer: 
Step-by-step explanation:
According to the empirical rule, the 95% confidence interval for the true population proportion is given by :-

Given : . The survey resulted in a sample proportion of p′=0.14, with a sampling standard deviation of σp′=0.02, who preferred reading an e-book.
Then, the 95% confidence interval for the true proportion of adults who prefer e-books will be :-

Hence, the 95% confidence interval for the true proportion of adults who prefer e-books= 
Step-by-step explanation:
8(7k+1)
no need to thank me
Answer:
y = -(x + 5)² + 4
Step-by-step explanation:
The roots are -3 and -7, so:
y = a (x + 3) (x + 7)
Distribute and complete the square:
y = a (x² + 10x + 21)
y = a (x² + 10x + 25 − 4)
y = a (x² + 10x + 25) − 4a
y = a (x + 5)² − 4a
The vertex is (-5, 4), so a = -1.
y = -(x + 5)² + 4