Please help with this I am so confused

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?

Acommunity group is building a garden on a rectangular lot of land. the lot measures 5x by 10x and the garden will be circular with a radius of 3x. how much of the land will be left over after the garden is built? a. 41 pi x^2 b. x^2 (50 - 9 pi) c. x^2 (50 - 3 pi) d. 41x^2

What is the the area of this triangle expressed as a monomial?