79. The magnitude M of an earthquake can be found using the equation M ( x ) = log ( x 0.001 ) m , open x close , equals log . open , x over 0.001 , close where x represents the seismograph reading of the earthquake in mm. An earthquake has a magnitude of 6.2. What is the seismograph reading of the earthquake in mm?
    6. 0.0062
    7. 0.0008
    8. 1.014
    9. 1584.9

80. A teacher's grading scale is shown below:

    Item	Percent of Total Grade
    Homework	5%
    Quizzes	10%
    Tests 1, 2, 3	20% each
    Final Exam	25%

    Sally's grade in the class was an 88. She earned a 97 on homework, 95 on quizzes, 85 on Test 1, 79 on Test 2 and 93 on Test 3. What was Sally's final exam grade?

    1. 22
    2. 66
    3. 79
    4. 89
81. There are 15 runners in a semifinal race where the top three runners advance to the finals. In how many ways could there be three runners that advance?
    6. 6
    7. 455
    8. 910
    9. 2730
82. What is the exact value of tan 240 ° ? tangent , 240 degrees question mark
    1. 2 2 fraction square root of 2 , over 2 end fraction
    2. 3 3 fraction square root of 3 , over 3 end fraction
    3. 1
    4. 3 square root of 3

83. Multiply [ 4 − 1 0 5 ] · [ 1 3 − 6 1 ] left bracket . table with 2 rows and 2 columns , row1 column 1 , 4 , column 2 negative 1 , row2 column 1 , 0 , column 2 5 , end table . right bracket . middle dot . left bracket . table with 2 rows and 2 columns , row1 column 1 , 1 , column 2 3 , row2 column 1 , negative 6 , column 2 1 , end table . right bracket

    6. [ 4 14 − 24 11 ] left bracket . table with 2 rows and 2 columns , row1 column 1 , 4 , column 2 14 , row2 column 1 , negative 24 , column 2 11 , end table . right bracket
    7. [ 4 − 3 0 5 ] left bracket . table with 2 rows and 2 columns , row1 column 1 , 4 , column 2 negative 3 , row2 column 1 , 0 , column 2 5 , end table . right bracket
    8. [ 10 − 30 11 5 ] left bracket . table with 2 rows and 2 columns , row1 column 1 , 10 , column 2 negative 30 , row2 column 1 , 11 , column 2 5 , end table . right bracket
    9. [ 10 11 − 30 5 ] left bracket . table with 2 rows and 2 columns , row1 column 1 , 10 , column 2 11 , row2 column 1 , negative 30 , column 2 5 , end table . right bracket

84. Consider the vectors u and v below.

    

    • Part A: Show the addition of the two vectors graphically. Label your answer w.
    • Part B: Using your answer from Part A, find − 0 . 5 w . negative 0 . 5 w .

85. Solve for x. Show or explain your work.

    2 ln 4 x + 5 = 8 4 x plus 5 equals 8

86. A pendulum initially swings through an arc that is 20 inches long. On each swing, the length of the arc is 0.85 of the previous swing.
    • Part A: Write a recursive model of geometric decay to represent the sequence of lengths of the arc of each swing. Let p 1 = 20 . p sub 1 , equals 20 .
    • Part B: Rewrite your model from Part A using an explicit formula.
    • Part C: What is the approximate total distance the pendulum has swung after 11 swings? Show your work.
    • Part D: What is the total distance, approximately, that the pendulum has swung when it stops? Show your work.
87. The equation of an ellipse is 4 x 2 + 9 y 2 + 8 x − 54 y + 49 = 0 . 4 x squared , plus , 9 y squared , plus 8 x minus 54 y plus . 49 equals 0 .
    • Part A: Write the equation in standard form. Show your work.
    • Part B: What are the foci and vertices of the ellipse? Show your work or explain your answer.
    • Part C: Graph the ellipse. Label the center of the ellipse on your graph.

88. Consider the following system of equations.

    { x + 2 z = − 1 y − 2 z = 2 2 x + y + z = 1 left brace . table with 3 rows and 1 column , row1 column 1 , x plus 2 z equals negative 1 , row2 column 1 , y minus 2 z equals 2 , row3 column 1 , 2 x plus y plus z equals 1 , end table

    • Part A: Represent the system of equations using the matrix equation A X = eh x equals B.
    • Part B: Find the determinant of the matrix A.
    • Part C: Solve the equation from Part A. If it cannot be solved, use your result from Part B to explain why.
89. Consider the function f ( x ) = 2 cos ( 4 x ) . f open x close equals 2 cosine open 4 x close .
    • Part A: What are the period and amplitude of the graph of f ( x ) ? f open x close question mark
    • Part B: Graph f ( x ) f open x close over two periods.
    • Part C: Solve f ( x ) = 0.5 f open x close equals 0.5 algebraically. Show your work and give your answer in radians.

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