1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Anastaziya [24]
3 years ago
12

Find the inverse of ????−7 −2

Mathematics
1 answer:
Masja [62]3 years ago
6 0

Answer:

A^{-1}=\begin{bmatrix}1 & 2\\ -4 & -7\end{bmatrix}

Step-by-step explanation:

A=\begin{bmatrix}-7 & -2\\ 4 & 1\end{bmatrix}

det\ A=-7\times 1-(-2)\times 4\\\Rightarrow det\ A=1

A^{-1}=\frac{1}{det\ A}\begin{bmatrix}1 & 2\\ -4 & -7\end{bmatrix}\\\Rightarrow A^{-1}=\frac{1}{1}\begin{bmatrix}1 & 2\\ -4 & -7\end{bmatrix}\\\Rightarrow A^{-1}=\begin{bmatrix}1 & 2\\ -4 & -7\end{bmatrix}

\therefore A^{-1}=\begin{bmatrix}1 & 2\\ -4 & -7\end{bmatrix}

A.A^{-1}=\begin{bmatrix}-7 & -2\\ 4 & 1\end{bmatrix}\times \begin{bmatrix}1 & 2\\ -4 & -7\end{bmatrix}\\\Rightarrow A.A^{-1}=\begin{pmatrix}\left(-7\right)\cdot \:1+\left(-2\right)\left(-4\right)&\left(-7\right)\cdot \:2+\left(-2\right)\left(-7\right)\\ 4\cdot \:1+1\cdot \left(-4\right)&4\cdot \:2+1\cdot \left(-7\right)\end{pmatrix}\\\Rightarrow A.A^{-1}=\begin{pmatrix}1&0\\ 0&1\end{pmatrix}

Hence, confirmed

You might be interested in
Find all the numbers such that the number added to itself is less than the number subtracted from 6
gizmo_the_mogwai [7]

Answer:

All numbers less than 2 or (-\infty, 1] or (-\infty, 2)

Step-by-step explanation:

Given that:

Number is added to itself is less than the number subtracted from 6.

To find:

All such numbers.

Solution:

Let the number be x.

Here, an inequality will be made.

When solved, it might give more than one answers.

As per the question statement, let us write the inequality.

Number added to itself \Rightarrow x +x =2x

Number subtracted from six = 6-x

As per question:

2x

So, the answer is:

All numbers less than 2 or (-\infty, 1] or (-\infty, 2).

4 0
3 years ago
Find the length of side x in simplest radical denominator
antiseptic1488 [7]

Answer:

324352

Step-by-step explanation:

8 0
3 years ago
Think of 5 positive integers that have a mode of 3, a median of 5, a mean of 7 and a range of 12.
kiruha [24]

For the mode to be 6, there has to be at least two 6s.

For the median to be 6, with two 6s, there must be at least one number above 6.

For the mean to be 6, the sum is 30, so the three remaining numbers must total 18.

3 0
2 years ago
What is true slope of (0,0) and (2,3)?
Mila [183]

Answer:

True slope=1.5

Step-by-step explanation:

1. 3-0=3

2. 2-0=2

3. 3/2

4. 1.5

5 0
3 years ago
{This question has been deleted}
stiks02 [169]

Answer:

this question isn't deleted yet

4 0
3 years ago
Read 2 more answers
Other questions:
  • I need help with this question please.
    5·1 answer
  • How many times does the graph of the quadratic function f(x) = x² - 9 intercept the x-axis?
    10·1 answer
  • Select all the factors of: 7x2 − 28 options: 7 7x (x + 2) (x − 2) (x2 + 4)
    5·1 answer
  • Solve: dy/dx − 2xy = x, with y(0) = 0.
    12·1 answer
  • I don’t understand how do you do this I have a assignment for tommorow some one help
    12·2 answers
  • Theodore earned $92.40 in interest after 4 years on a principal of $550. What is the interest rate (%)?
    5·1 answer
  • What property is shown k*(7-9)=(k*7)-(k*9)
    13·2 answers
  • Nate is saving up to purchase a new computer. He has $175 already and can 1 point save $20 per month. How long will it take him
    10·1 answer
  • A chef has 6 blocks of butter. Each block weighs 1 pound. She cuts each block into fifths. How many15-pound pieces of butter doe
    12·1 answer
  • riangle A″B″C″ is formed using the translation (x + 0, y + 2) and the dilation by a scale factor of 2 from the origin. Which equ
    6·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!