Please help easy math 15 pts each The altitude a (in feet) of a plane t minutes after liftoff is given by a=3400t+600. How many minutes after liftoff is the plane at an altitude of 21,000 feet?

The plane reaches an altitude of 21,000 feet (answer) minutes after liftoff.

the central idea is that:

individuals should refuse to cooperate with institutions they believe unjust.

thoreau felt  that governments were more often agents of corruption than justice, even democracies, and that just because the majority feels a certain way does not make it just or correct in absolute terms. he uses the fact that slavery exists in our democracy to support this idea.

he goes on to say that, as a result, people should live true to their own internal laws regarding right and wrong, as a product of reflection and a moral life, rather than following every law that society imposes. 

step-by-step explanation:

according to egenuity the answer is

step-by-step explanation:

d. 344.22