The altitude a (in feet) of a plane i minutes after liftoff is given by
a = 34001 + 600. How many minutes
after liftoff is the plane
at an altitude of
21.000 feet?

Step-by-step explanation:

a=3400t+600, we put in 21,000 for a. Because we have to find 't' when 'a' is 21,000.

which will give us  21,000 = 3400t+600.

Then,Subtract 600 to both sides to get 20,400 = 3400t

Divide both sides by 3,400 and you get 6 = t.

The ans is 6 minutes. The plane will take 6 min to reach the altitude 21,000 feet

step-by-step explanation: