Help! I’m trying to help my friend get caught up who had been ill.

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?

What is the remainder when 3x^2-x-10 is divided by x-1 -6,-7,-8, or -9

87.5% , 100% , 83.33 , 93.33% , 100% , 82.5% are all the academic points i've gotten this quarter. what's my final grade?