Use what you know about addition and subtraction of polynomials to find the missing term represented by the question mark in each equation. (–4x2 + 6x + 3) + (8x + 5 + ?) = 2x2 + 14x + 8 ? = (–b3 + 3b2 + 8) – (? – 5b2 – 9) = 5b3 + 8b2 + 17

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?