Plssssss help I’m timed

In-s [12.5K]

ANSWER

24

EXPLANATION

For a matrix A of order n×n, the cofactor $C_{ij}$ of element $a_{ij}$ is defined to be

$C_{ij} = (-1)^{i+j} M_{ij}$

$M_{ij}$ is the minor of element $a_{ij}$ equal to the determinant of the matrix we get by taking matrix A and deleting row i and column j.

Here, we have

$C_{11} = (-1)^{1+1} M_{11} = M_{11}$

M₁₁ is the determinant of the matrix that is matrix A with row 1 and column 1 removed. The bold entries are the row and the column we delete.

$\begin{aligned} A=\begin{bmatrix} \bf 1 & \bf -6 & \bf -4\\ \bf 7 & 0 & -3 \\ \bf -9 & 8 & -8 \end{bmatrix} \implies M_{11} &= \text{det}\left(\begin{bmatrix} 0&-3 \\ 8&-8 \end{bmatrix} \right) \end{aligned}$

Since the determinant of a 2×2 matrix is

$\det\left( \begin{bmatrix} a & b \\ c& d \end{bmatrix} \right) = ad-bc$

it follows that

$\begin{aligned} A=\begin{bmatrix} \bf 1 & \bf -6 & \bf -4\\ \bf 7 & 0 & -3 \\ \bf -9 & 8 & -8 \end{bmatrix} \implies M_{11} &= \text{det}\left(\begin{bmatrix} 0&-3 \\ 8&-8 \end{bmatrix} \right) \\ &= (0)(-8) - (-3)(8) \\ &= -(-24) \\ &= 24 \end{aligned}$

so $C_{11} = M_{11} = 24$

4 0

3 years ago

The following table shows how the average constituency changes for two regional governing boards, joshua and salinas, when a new

AVprozaik [17]

The relative unfairness of an apportionment that gives a new board member to joshua rather than to salinas will be

<h3>How to calculate the values?</h3>

The relative unfairness of an apportionment that gives a new board member to joshua rather than to salinas will be:

= (1520 - 1232)/1232

= 288/1232

= 0.234

The relative unfairness of an apportionment that gives a new board member to salinas rather than to Joshua will be:

= (1448 - 1333)/1333

= 115/1333

= 0.086

The regional governing board that should receive the new board member is Salinas.

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5 0

2 years ago

If 2x +y=8, x+2y=4, find the value of x-y.<br> Please, help me

kifflom [539]

y = 8 -2x

x + 2 (8 - 2x) = 1

x + 16 - 4x = 1

x - 4x = -15

-3x = -15

x = 5

If x = 5, then we can substitute in...

5 + 2y = 1

2y = -4

y = -2

Now let us check that by substituting those values in to the equation

2x + y = 8

2 (5) + (-2) = 8

That is correct so we have the right values for x and y/

8 0

3 years ago

5 pints of blue paint with 2 pints of yellow paint make green how many pints of blue paint are needed to make 28 pints of green

zhuklara [117]

145 blue paint are needed to make 28 pints of green paint

3 0

3 years ago

What is the inverse of the following statement?

Ksju [112]

The inverse of the statement is 'If it is Wednesday, then it is not sunny'

<h3>What is the inverse of a word?</h3>

The inverse of a word is simply the contrary nature or quality and could be termed opposite or reverse of a proposition or theorem that is formed by'

contradicting both the subject and predicate
Contradicting both the hypothesis and conclusion of a given proposition or theorem

For instance, the inverse of "if A then B" is "if not-A then not-B" and 'if not A, then B" is 'If A, not B ' is termed a compare contrapositive

From the information given, we have;

'If it is not Wednesday, then it is sunny'

We can see that the inverse of the proposition is;

'If it is Wednesday, then it is not sunny'

Thus, the inverse of the statement is 'If it is Wednesday, then it is not sunny'

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6 0

2 years ago