The current number of coupons being mailed out by a company each week in one region of the country can be represented by the function R(x) = 3x2 + 21x
where x is the number of cities in the region. The number of coupons in a new mailing sent only to preferred customers can be represented by the function
P(x) = 9x.

Which function best describes C(x), the number of coupons that are shipped out in any given week?
A. C(x) = 3x²+ 30x
B. C(x) = 12x² + 21x
C. C(x) = 3x² + 12x
D. C(x) = -6x² + 21x

Aspacecraft can attain a stable orbit 300 kilometers above earth if it reaches a velocity of 7.7 kilometers per second. the formula for a rocket's maximum velocity v in kilometers per second is vequalsminus0.0098tplusc ln upper r, where t is the firing time in seconds, c is the velocity of the exhaust in kilometers per second, and r is the ratio of the mass of the rocket filled with fuel to the mass of the rocket without fuel. find the velocity of a spacecraft whose booster rocket has a mass ratio of 20, an exhaust velocity of 2.1 km/s, and a firing time of 15 s. can the spacecraft achieve a stable orbit 300 km above earth?