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Exam 6 Sections 5.2, 6.1, 6.2, 6.7
100 Points Name___________________________________
This test is due first thing Monday morning, 8:10
sharp. It is hoped that this test will
be a learning experience for you. :o)
SHORT ANSWER.
Write the word or phrase that best completes each statement or answers
the question.
Find an equation of the parabola described.
1)
Focus at ( 4, 0);
vertex at (0, 0)
MULTIPLE CHOICE.
Choose the one alternative that best completes the statement or answers
the question.
Match the equation to the graph.
2)
= 8(y + 1)
A)
B)
C)
D)
SHORT ANSWER.
Write the word or phrase that best completes each statement or answers
the question.
Find the vertex, focus, and directrix of the
parabola.
3)
= 12y
Find an equation for the parabola described.
4)
Vertex at ( 5,
2); focus at ( 3, 2)
Find the vertex, focus, and directrix of the
parabola with the given equation.
5)
= 12(x - 1)
Find the vertex, focus, and directrix of the
parabola. Graph the equation.
6)
- 6x = 4y -
37
Solve the problem.
7)
A reflecting telescope contains a mirror shaped like
a paraboloid of revolution. If the mirror is
16 inches across at its opening and is
3 feet deep, where will the light be concentrated?
Hint: Convert feet to inches. We're asking you where the focus is.
Verify that the values of the variables listed
are solutions of the system of equations.
8)
x = -2, y = 5
Solve the system of equations by using
substitution.
9)
Use the elimination method to solve the system.
10)
Hint: Divide the first equation by 2 in your first step.
Identify variables in words and units. Write the system of equations.
11)
The
The following system has no solution. Explain how you can tell. What's the geometry of this situation?
12)
Solve the system of equations.
13)
Identify variables and write the system of
equations for the following problem.
14)
Lexie wants to have an income of $9000 per year from
investments. To that end she is going to invest $90,000 in three different
accounts. These accounts pay 7%, 10%, and 14% simple interest. If she wants to
have $10,000 more in the account paying 7% simple interest than she has in the
account paying 14% simple interest, how much should go into each account?
Explain how you can tell that #15 has no
solution.
15)
This system has infinitely many solutions. Solve it and state the general solution, for
instance,
x = 3z - 2, y = 2z +
7, z =
any real number.
16)
Write the augmented matrix for the system. Do not solve.
17)
Write the system of equations associated with the
augmented matrix. Do not solve.
18)
Perform the row operation(s) on the given
augmented matrix.
19)
=
20)
= 4
+
Graph the inequality.
21)
3x + 5y ≤ 15
22)
y > + 3
Graph the system of inequalities.
23)
1)
y2 =
16x
2)
A
3)
vertex: (0, 0)
focus: (0, 3)
directrix: y = -3
4)
= -8(x - 5)
5)
vertex: ( 1, 3)
focus: ( 4, 3)
directrix: x = -2
6)
vertex: ( 3, 7)
focus: ( 3, 8)
directrix: y = 6
7)
0.4 in. from the vertex
8)
solution
9)
x = 5, y = -2
10)
x = 8, y = -8
11)
316 senior citizens
12)
inconsistent (no solution)
13)
x = 1, y = -5, z = 4
14)
$40,000 at 7%, $20,000 at 10%, $30,000 at 14%
15)
inconsistent (no solution)
16)
x = -3z - 5
y = z + 2
z = any real number
17)
18)
19)
20)
21)
22)
23)