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Diano4ka-milaya [45]

3 years ago

11

I need help with this, I do not understand it so whoever answers this question, thank you. Whoever answers correctly and is firs

t, I will give brainliest.

2 answers:

Brilliant_brown [7]3 years ago

8 0

I think the answer is B

erma4kov [3.2K]3 years ago

3 0

I think it’s choice A

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Help please!!!!!!!!!

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

Garica family bought 9 bags of cookies each bag had 15 cookies they have eaten 27 of the cookies how many cookies do they have l

vova2212 [387]

108 because 9 x 15 is 135 then 135- 27 is 108

3 0

3 years ago

Sophia finished 2/3 of a book. She calculated that she finished 90 more pages than she has yet to read. How long is her book?

TEA [102]

Answer:

The book is 270 pages long.

6 0

3 years ago

Two 120 resistors are connected in parallel across voltage supply of 10 vdc what’s the current in this circuit

Daniel [21]

Answer: 0.167

Step-by-step explanation:

This is an applied mathematics question

Resistors in parallel ⁾/R = ¹/₁₂₀ + ¹/₁₂₀ since the resistor is two 120

Therefore , resolve into fraction now yield

¹/R = 1 + 1

-------

120

= 2/120

= ¹/₆₀

Therefore, ¹/R = ¹/₆₀

Cross multiply to get R the resistance

R = 60

From formula, V = IR where I is the current

There fore making I the subject of the formula

I = V/R

= 10/60

= 0.166

= 0.167 A, A = ampere which is the unit of current.

4 0

3 years ago

Angle 1 and angle 2 are complementary angles. The measure of angle 1 is 58°. The measure of angle 2 is 2x°. Find the value of x

Tamiku [17]

Answer:

2x+58+x=180 180-58=3x 122=3x

Step-by-step explanation:

x=40.666

*the sum of the angles of the triangle is 180 degrees

8 0

3 years ago