Exam 7: Systems of Equations and Matrices

arrow
  • Select Tags
search iconSearch Question
flashcardsStudy Flashcards
  • Select Tags

{xy=30x+y=11\left\{ \begin{array} { l } x y = 30 \\x + y = 11\end{array} \right.

(Multiple Choice)
4.8/5
(41)

We have encoded a message by assigning the numbers 1 - 26 to the letters a - z of the alphabet, respectively, and assigning 27 to a blank space. We have further encoded it by using an encoding matrix. Decode this message by finding the inverse of the encoding matrix and multiplying it times the coded message. -The encoding matrix i A=[122132123] and the encoded message is 88,103,115,84,99,104,41,43,46,40,49,45A = \left[ \begin{array} { l l l } 1 & 2 & 2 \\1 & 3 & 2 \\1 & 2 & 3\end{array} \right] \text { and the encoded message is } 88,103,115,84,99,104,41,43,46,40,49,45 86, 91, 113, 52, 61, 65.

(Short Answer)
4.7/5
(43)

We can encode a message by assigning the numbers 1 - 26 to the letters a - z of the alphabet, respectively, and assigning 27 to a blank space. To further encode a message, we can use an encoding matrix A to convert these numbers into new pairs or triples of numbers. Use matrix A to encode the given message. -Use the matrix A A=[422312321]A = \left[ \begin{array} { r c c } 4 & 2 & - 2 \\- 3 & 1 & 2 \\3 & - 2 & 1\end{array} \right] to encode the message "Thank you" into triples of numbers. Combine the triples of numbers to give the encoded numerical message.

(Short Answer)
4.8/5
(26)

Find the indicated sum or difference, if it is defined. - [291][43]\left[ \begin{array} { l l l } - 2 & 9 & 1 \end{array} \right] - \left[ \begin{array} { l l } 4 & 3 \end{array} \right]

(Multiple Choice)
4.9/5
(35)

Linda invests $25,000 for one year. Part is invested at 5%, another part at 6%, and the rest at 8%. The total income from all 3 investments is $1600. The total income from the 5% and 6% investments is equal to the income From the 8% investment. Find the amount invested at each rate.

(Multiple Choice)
4.9/5
(36)

A=[725] and B=[139124122]A = \left[ \begin{array} { l l l } - 7 & - 2 & 5\end{array} \right] \text { and } B = \left[ \begin{array} { r r r } - 1 & - 3 & - 9 \\1 & 2 & - 4 \\1 & - 2 & - 2\end{array} \right]

(Multiple Choice)
4.9/5
(42)

Find the inverse matrix of A. - A=[2366]A = \left[ \begin{array} { r r } - 2 & 3 \\- 6 & - 6\end{array} \right]

(Multiple Choice)
4.9/5
(37)

A company offers three mutual fund plans for its employees. Plan I consists of 2 blocks of common stocks, 3 municipal bonds, and 4 blocks of preferred stock. Plan II consists of 2 blocks of common stocks, 2 municipal Bonds, and 1 block of preferred stock. Plan III consists of 4 blocks of common stocks, 5 municipal bonds, and 5 Blocks of preferred stock. An employee combined these plans so that he has 22 blocks of common stock, 27 Municipal bonds, and 26 blocks of preferred stock. How many units of plan III might he have?

(Multiple Choice)
4.8/5
(29)

Decide whether or not matrix A and matrix B are inverses. - A=[2444] and B=[1/21/41/21/4]\mathrm { A } = \left[ \begin{array} { r r } - 2 & 4 \\4 & - 4\end{array} \right] \text { and } \mathrm { B } = \left[ \begin{array} { l l } 1 / 2 & 1 / 4 \\1 / 2 & 1 / 4\end{array} \right]

(Multiple Choice)
4.8/5
(34)

Use an inverse matrix to find the solution to the system. - {5xy7z=356x+6z=125y+z=7\left\{ \begin{array} { c } - 5 x - y - 7 z = - 35 \\- 6 x + 6 z = - 12 \\5 y + z = 7\end{array} \right.

(Multiple Choice)
4.7/5
(36)

{x2y2=39xy=3\left\{ \begin{array} { l } x ^ { 2 } - y ^ { 2 } = 39 \\x - y = 3\end{array} \right.

(Multiple Choice)
4.8/5
(33)

Solve for x. - 24x3=2\left| \begin{array} { l l } 2 & 4 \\x & 3\end{array} \right| = - 2

(Multiple Choice)
4.8/5
(44)

Find the solution or solutions, if any exist, to the system. - {7x+7y+z=1x+8y+8z=89x+y+9z=9\left\{ \begin{array} { l } 7 x + 7 y + z = 1 \\x + 8 y + 8 z = 8 \\9 x + y + 9 z = 9\end{array} \right.

(Multiple Choice)
4.8/5
(36)

Solve the system graphically. -A rectangular metal sheet has an area of 150 square centimeters. Four squares with sides 2 cm2 \mathrm {~cm} are cut from the corners of the sheet, and the edges are bent upward to form an open box with a volume of 132 cubic centimeters. Find the dimensions of the box.

(Multiple Choice)
4.8/5
(26)

first two games of the season. Write a matrix containing the total number of points and rebounds for each of the starting five. Game 1 Points Rebounds Levy 20 3 Cowens 16 5 Williams 8 12 Miller 6 11 Jenkins 10 2 Game 2 Points Rebounds Levy 18 4 Cowens 14 3 Williams 12 9 Miller 4 10 Jenkins 10 3 A) [562]\left[ \begin{array} { l l } 5 & 62 \end{array} \right] В) [73830821202110520]\left[ \begin{array} { r r } 7 & 38 \\ 30 & 8 \\ 21 & 20 \\ 21 & 10 \\ 5 & 20 \end{array} \right] C) [38730820211021205]\left[ \begin{array} { r r } 38 & 7 \\ 30 & 8 \\ 20 & 21 \\ 10 & 21 \\ 20 & 5 \end{array} \right] D) [625][ 625 ] Answer: C -The table below gives the median annual incomes for men and women in three cities in 2001. Assume that in 2002, the median annual incomes increased by 7% in all categories. Create a matrix that represents the median Annual incomes for 2002. Round numbers to the nearest dollar. Men Women City 1 \ 35,562 \ 31,652 City 2 31,277 26,433 City 3 26,571 24,140

(Multiple Choice)
4.9/5
(43)

A basketball fieldhouse seats 15,000. Courtside seats sell for $8, endzone for $7, and balcony for $5. A full house earns $88,000 in ticket revenue. If half the courtside and balcony seats and all the endzone seats are sold, the Total ticket revenue is $51,000. How many of each type of seat are there?

(Multiple Choice)
4.8/5
(39)

A psychologist studying the effects of good nutrition on the behavior of rabbits feeds one group a combination of three foods, I, II, and III. Each of these foods contains three additives, A, B, and C, that are used in the study. The table below gives the percent of each additive that is present in each food. If the diet being used requires 19)1 g per day of A, 8.94 g of B, and 14.02 g of C, find the number of grams of food II that should be used each Day) Let z represent the number of grams of food III. Food I| Food II Food III Additive A 10\% 10\% 11\% Additive B 6\% 2\% 15\% Additive C 8\% 6\% 13\%

(Multiple Choice)
4.9/5
(42)

Find the value of the determinant. - 4301\left| \begin{array} { l l } 4 & - 3 \\ 0 & 1 \end{array} \right|

(Multiple Choice)
4.8/5
(35)

first two games of the season. Write a matrix containing the total number of points and rebounds for each of the starting five. Game 1 Points Rebounds Levy 20 3 Cowens 16 5 Williams 8 12 Miller 6 11 Jenkins 10 2 Game 2 Points Rebounds Levy 18 4 Cowens 14 3 Williams 12 9 Miller 4 10 Jenkins 10 3 A) [562]\left[ \begin{array} { l l } 5 & 62 \end{array} \right] В) [73830821202110520]\left[ \begin{array} { r r } 7 & 38 \\ 30 & 8 \\ 21 & 20 \\ 21 & 10 \\ 5 & 20 \end{array} \right] C) [38730820211021205]\left[ \begin{array} { r r } 38 & 7 \\ 30 & 8 \\ 20 & 21 \\ 10 & 21 \\ 20 & 5 \end{array} \right] D) [625][ 625 ] Answer: C -Barnes and Able are partners that sell life, health, and auto insurance. The tables below show their sales figures for May and June. Find the matrix that gives total sales for the two months. \quad \quad \quad \quad \quad \quad  May Sales ($) \text { May Sales (\$) } Life Health Auto Able 20,000 15,000 7000 Barnes 30,000 0 17,000 \quad \quad \quad \quad \quad \quad  June Sales ($) \text { June Sales (\$) } Life Health Auto Able 70,000 0 30,000 Barnes 30,000 22,000 32,000

(Multiple Choice)
4.8/5
(27)

Solve the system graphically. - {xy+5x=24yx+y=54\left\{ \begin{array} { l } x y + 5 x = 24 \\\frac { y } { x } + y = \frac { 5 } { 4 }\end{array} \right.  Solve the system graphically. - \left\{ \begin{array} { l }  x y + 5 x = 24 \\ \frac { y } { x } + y = \frac { 5 } { 4 } \end{array} \right.

(Multiple Choice)
4.7/5
(43)
Showing 141 - 160 of 196
close modal

Filters

  • Essay(0)
  • Multiple Choice(0)
  • Short Answer(0)
  • True False(0)
  • Matching(0)