the first five terms of an arithmetic sequence are -1,3,7,11,15. write down, in terms of n, an expression for the nth term in this sequence

The standard deviation for a set of data is 5.5. the mean is 265. what is the margin of error?

I'm at a bookstore with $\$35$ in my pocket and a $20\%$-off coupon. what is the cost of the most expensive book i can buy with my money and the coupon? (assume that there are books of every possible price in the bookstore. it's a large bookstore! )

Tim earns $120 plus $30 for each lawn he mows.write an iniqualityvto represent how many lawns he needs to mow to make more than $310