Ineed only an expert to answer these questions i will give 20 pts and the brainlest answer if there right

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?

The scatter plot shows the number of animal cells clara examined in a laboratory in different months: plot ordered pairs 1, 20 and 2, 60 and 3,100 and 4, 140 and 5, 180 what is the approximate predicted number of animal cells clara examined in the 9th month?

Which shows one way to determine the facts of x3+4x2+5x+20 by grouping