Answer:

Step-by-step explanation:
Given


Required:
Determine the time taken to return to the ground
From the equation given; height (h) is a function of time (t)
When the rocket returns to the ground level, h(t) = 0
Substitute 0 for h(t) in the given equation

becomes

Solve for t in the above equation

Factorize the above expression

Split the expression to 2

Solving the first expression

Divide both sides by -4



Solving the second expression

Add 30 to both sides


Divide both sides by 4



Hence, the values of t are:
and 
shows the time before the launching the rocket
while
shows the time after the rocket returns to the floor
Answer:
500
Step-by-step explanation:
510=x+.21x-.19x
510=(1+.21-.19)X
510=1.02X
X=510/1.02
X=500
System of Equations
For the problem to solve we'll use the following variables:
x = number of the early bird tickets sold
y = number of the regular tickets sold
Haley sold a total of 20 tickets, thus:
x + y = 20 [1]
Early bird tickets cost $10 and regular tickets cost $15, thus the total money collected is:
10x + 15y = 225
Dividing by 5:
2x + 3y = 45 [2]
We have to solve the system of equations [1] and [2].
Multiply [1] by -2:
-2x - 2y = -40 [3]
Add [3] to [2]:
-2x - 2y +2x + 3y = -40 + 45
Simplifying:
y = 5
Substituting in [1]:
x + 5 = 20
Subtracting 5:
x = 20 - 5
x = 15
Solution: Hayley sold 15 early bird tickets and 5 regular-priced tickets
The order pair solution is (15,5)
Answer:
Area = pi r squared
Step-by-step explanation:
If you need to, sometimes your teacher will ask you to leave you answers in terms of pi, or keep pi as 3.