Step-by-step explanation:
For a quadratic equation y = ax² + bx + c, the vertex (the maximum or minimum point) is at x = -b/(2a).
1) y = -0.5t² + 2t + 38
The maximum is at:
t = -2 / (2 × -0.5)
t = 2
The maximum height is:
y = -0.5(2)² + 2(2) + 38
y = 40
The coordinates of the vertex are (2, 40). That means the missile reaches a maximum height of 40 km after 2 minutes.
2) y = -4.9t² + 12t + 1.6
The maximum is at:
t = -12 / (2 × -4.9)
t = 1.22
The maximum height is:
y = -4.9(1.22)² + 12(1.22) + 1.6
y = 8.95
The coordinates of the vertex are (1.22, 8.95). That means the missile reaches a maximum height of 8.95 m after 1.22 seconds.
3) y = -0.04x² + 0.88x
The maximum is at:
x = -0.88 / (2 × -0.04)
x = 11
The maximum height is:
y = -0.04(11)² + 0.88(11)
y = 4.84
The maximum height of the tunnel is 4.84 meters.
The maximum width is when y = 0.
0 = -0.04x² + 0.88x
0 = -0.04x (x − 22)
x = 22
The maximum width is 22 feet.

Step-by-step explanation:
The elements of matrices are represented in the form

Here r is the row number and c is the column number.
Given matrix is:
![A = \left[\begin{array}{ccc}3&6&9\\2&4&8\end{array}\right]](https://tex.z-dn.net/?f=A%20%3D%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D3%266%269%5C%5C2%264%268%5Cend%7Barray%7D%5Cright%5D)
The elements of matrix will be represented by a_{r,c}
We have to find 
Which means that the first row and third column.
The first row is: 3 6 9 and the element in third column is: 9
So,

Keywords: Matrices, Elements
Learn more about matrices at:
#LearnwithBrainly
The correct answer is 427
Answer:
a) Bar chart
b) Histogram
c) Bar chart
d) Histogram
Step-by-step explanation:
a) Trash pick-up DAY for each HOUSEHOLD in Ames - This is categorical data because, we are talking about days of the week. For instance, Household 1 might have Sunday as Trash pick-up day and that could be accumulated into frequency. Hence, BAR chart is the most appropriate.
b) Patient WAIT-TIME at ISU. This is continuous (quantitative) data. And the most appropriate is HISTOGRAM.
c) Number of trips taken during a GIVEN SCHOOL YEAR by EACH ISU STUDENT. Let say we have 5 ISU STUDENTS. Student 1 had 5 trips, student 2 had 10 trips, etc.
We want to see which student has the most and least trip in that particular school year. Although is count data but the most appropriate graphical display is BAR chart.
d) TAX BRACKET of ALL Iowa RESIDENTS. This is a continuous (quantitative) data. The most appropriate graphical display is HISTOGRAM.