What are the roots of this equation? x^2-4x+9=0

A. 1 +/- i_/5
B. 2 +/- i_/5
C. 2 +/- i_/3
D. 1 +/- i_/52

Which is f(5) for the function –2x2 + 2x - 3?

Find the greatest common factor of the followig monomials 46g^2h and 34g^6h^6

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?