What is the simplified form of the following expression? Assume a greater-than-or-equal-to 0 and c greater-than-or-equal-to 0 EXPRESSION: 14 (RootIndex 4 StartRoot a Superscript 5 Baseline b squared c Superscript 4 Baseline EndRoot) minus 7 a c (RootIndex 4 StartRoot a b squared EndRoot)

OPTIONS
A. 7 a c (RootIndex 4 StartRoot a b squared EndRoot)
B. 7 (RootIndex 4 StartRoot a b squared EndRoot)
C. Negative 7 (RootIndex 4 StartRoot a b squared EndRoot)
D. Negative 7 a c (RootIndex 4 StartRoot a b squared EndRoot)

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?