Answer:
the rocket will reach its maximum height after 4 seconds.
Step-by-step explanation:
The first term ( -4.9(t-4)^2 ) can never be positive, so the maximum height of 80 meters is achieved when t = 4.
Answer:
number 3
Step-by-step explanation:
Multiply the equation:

The solution set is the same, because multiplying both sides of an equation by a non-zero number doesn't change the solution set. In fact, if you rewrite the equation as

Multiplying this by 3 (or whatever number, for all it matters) gives

Now, a product is zero if and only if at least one of the factor is zero. So, either
or 
Since the first is clearly impossible, the second one must be true, which is the original equation.
(left table) the first one is add 1(on left) and add 4 (on right)
(right table) then the second on is
add 1(on left) and add 3 (on right)
Answer:
1 hour and 4 minutes
Step-by-step explanation: