What is the formula for the following arithmetic sequence? -9, -2, 5, 12, ...

an = -9 + 7( n - 1)
an = -9 + (-7)( n - 1)
an = 7 + (-9)( n - 1)
an = 9 + (-7)( n - 1)

Find the roots of the polynomial function f(x) = x^3 + 2x^2 + x

The anwser cause i do not understand just plez

Juanita wade's new car has an msrp of $28,902.11 including title and processing fees. the premier package which includes surround sound and dvd player costs three times the amount of the in-style package which includes leather seats and select wheels. the total cost of her new car was $34,290.08 which included the 6.5% sales tax. find the cost of the premier package to the nearest cent.