Let x and y be two supplementary angles, where the measure of x is three times the measure of y. Which system of equations below could be used to find the measure of the two angles? A. x + y = 180
x = y + 3

B. x + y = 180
y = 3x

C. x + y = 180
y = x + 3

D. x + y = 180
x = 3y

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?