Li believes that the graph shows a direct variation. On a coordinate plane, a line goes through points (0, 1) and (2, 0).

Why is Li incorrect in saying that the graph shows a direct variation?
The graph does not have a constant rate of change.
When the x-value is 0, the y-value is 1.
The slope is negative.
The relationship is proportional.

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?