I need help does anyone know how to do this answer 4x + 2x = 3x - 15

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 actual length of side y is 22 cm. use the scale drawing to find the actual length of side x. a) 15.2 cm b) 17.1 cm c) 18.0 cm d) 28.3 cm

Situation: find the age of the skull to the nearest year, enter the correct answer. a hiker in africa discovers a skull that contains 32% of its original amount of c- 14. done n = noekt 00000 no = inital amount of c-14 (at time t = 0) n = amount of c-14 at time t k = 0.0001 t = time, in years