Question
upstudy study bank question image url

(6) F \( M=\left|\begin{array}{cc}-1 & -5 \\ 3 & 2\end{array}\right| \) and \( m=\left(\left.\begin{array}{ll}0 & 4 \\ 6 & 3\end{array} \right\rvert\,\right. \) find \( \left|\begin{array}{ll}3 m-A\end{array}\right| \)

Ask by Lynch Greene. in the United States
Mar 12,2025

Upstudy AI Solution

Tutor-Verified Answer

Answer

The determinant of \(3m - A\) is \(-248\).

Solution

Let \[ A=\begin{pmatrix}-1 & -5\\3 & 2\end{pmatrix}\quad\text{and}\quad m=\begin{pmatrix}0 & 4\\6 & 3\end{pmatrix}. \] We want to compute \[ \left|\,3m-A\,\right|. \] **Step 1. Compute \(3m\).** Multiply each entry of \(m\) by 3: \[ 3m = 3\begin{pmatrix}0 & 4\\6 & 3\end{pmatrix} = \begin{pmatrix}3\cdot 0 & 3\cdot 4\\3\cdot 6 & 3\cdot 3\end{pmatrix} = \begin{pmatrix}0 & 12\\18 & 9\end{pmatrix}. \] **Step 2. Compute \(3m-A\).** Subtract the corresponding entries of \(A\) from \(3m\): \[ 3m-A = \begin{pmatrix}0 & 12\\18 & 9\end{pmatrix} - \begin{pmatrix}-1 & -5\\3 & 2\end{pmatrix} = \begin{pmatrix}0-(-1) & 12-(-5)\\18-3 & 9-2\end{pmatrix}. \] Thus, \[ 3m-A = \begin{pmatrix}1 & 17\\15 & 7\end{pmatrix}. \] **Step 3. Compute the determinant of \(3m-A\).** For a \(2\times 2\) matrix \[ \begin{pmatrix}a & b\\c & d\end{pmatrix}, \] the determinant is given by \(ad-bc\). Here, we have: \[ \left|3m-A\right| = 1\cdot 7 - 17\cdot 15. \] Calculate: \[ 1\cdot 7 = 7,\quad 17\cdot 15 = 255. \] Thus, \[ \left|3m-A\right| = 7 - 255 = -248. \] The final answer is \[ \boxed{-248}. \]

Answered by UpStudy AI and reviewed by a Professional Tutor

error msg
Explain
Simplify this solution

The Deep Dive

To find \( |3m - A| \), we will first compute \( 3m \) and then subtract matrix \( A \), where \( A = \left|\begin{array}{cc}-1 & -5 \\ 3 & 2\end{array}\right| \). First, let's calculate \( 3m \): \[ m = \left(\begin{array}{cc} 0 & 4 \\ 6 & 3 \end{array}\right) \implies 3m = 3 \cdot \left(\begin{array}{cc} 0 & 4 \\ 6 & 3 \end{array}\right) = \left(\begin{array}{cc} 0 & 12 \\ 18 & 9 \end{array}\right). \] Now, we can write the matrix \( A \): \[ A = \left(\begin{array}{cc} -1 & -5 \\ 3 & 2 \end{array}\right). \] Next, we need to calculate \( 3m - A \): \[ 3m - A = \left(\begin{array}{cc} 0 & 12 \\ 18 & 9 \end{array}\right) - \left(\begin{array}{cc} -1 & -5 \\ 3 & 2 \end{array}\right) = \left(\begin{array}{cc} 0 - (-1) & 12 - (-5) \\ 18 - 3 & 9 - 2 \end{array}\right) = \left(\begin{array}{cc} 1 & 17 \\ 15 & 7 \end{array}\right). \] Finally, we need to find the determinant of \( 3m - A \): \[ |3m - A| = \left| \begin{array}{cc} 1 & 17 \\ 15 & 7 \end{array} \right| = (1 \cdot 7) - (17 \cdot 15) = 7 - 255 = -248. \] Thus, the final answer is: \[ \left| 3m - A \right| = -248. \]

Try Premium now!
Try Premium and ask Thoth AI unlimited math questions now!
Maybe later Go Premium
Study can be a real struggle
Why not UpStudy it?
Select your plan below
Premium

You can enjoy

Start now
  • Step-by-step explanations
  • 24/7 expert live tutors
  • Unlimited number of questions
  • No interruptions
  • Full access to Answer and Solution
  • Full Access to PDF Chat, UpStudy Chat, Browsing Chat
Basic

Totally free but limited

  • Limited Solution
Welcome to UpStudy!
Please sign in to continue the Thoth AI Chat journey
Continue with Email
Or continue with
By clicking “Sign in”, you agree to our Terms of Use & Privacy Policy