Which ordered pair is a solution to the equation y = 2x + 1? A. (8, 17)
B. (9,16)
C. (10, 12)
D. (13, 17)

(a) solve h+2/6 = h-3/4(b) solve the following simultaneous equations. 2x = y + 66x - 2y = 13x = ? y = ?

Math i have no idea how to do a and b

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?