Explore Westonci.ca, the premier Q&A site that helps you find precise answers to your questions, no matter the topic. Experience the convenience of finding accurate answers to your questions from knowledgeable experts on our platform. Experience the ease of finding precise answers to your questions from a knowledgeable community of experts.

Solve each equation and check your answers.

[tex]\[ \begin{pmatrix} 2 & 1 \\ 3 & -4 \end{pmatrix} - 3X = \begin{pmatrix} 9 & -67 \\ 1 & -2 \end{pmatrix} \][/tex]


Sagot :

To solve for the unknown matrix [tex]\(X\)[/tex] in the equation

[tex]\[ \left[\begin{array}{cc} 2 & 1 \\ 3 & -4 \end{array}\right] - 3X = \left[\begin{array}{cc} 9 & -67 \\ 1 & -2 \end{array}\right], \][/tex]

we'll follow these steps:

### Step 1: Write the Given Equation in Matrix Form

The equation given is:
[tex]\[ A - 3X = B, \][/tex]
where [tex]\(A\)[/tex] and [tex]\(B\)[/tex] are known matrices:
[tex]\[ A = \left[\begin{array}{cc} 2 & 1 \\ 3 & -4 \end{array}\right] \][/tex]
[tex]\[ B = \left[\begin{array}{cc} 9 & -67 \\ 1 & -2 \end{array}\right]. \][/tex]

### Step 2: Isolate [tex]\(3X\)[/tex]

We isolate [tex]\(3X\)[/tex] by subtracting matrix [tex]\(B\)[/tex] from matrix [tex]\(A\)[/tex]:
[tex]\[ A - B = 3X. \][/tex]

Since matrix subtraction is done element-wise, let's compute [tex]\(A - B\)[/tex]:

[tex]\[ A - B = \left[\begin{array}{cc} 2 & 1 \\ 3 & -4 \end{array}\right] - \left[\begin{array}{cc} 9 & -67 \\ 1 & -2 \end{array}\right]. \][/tex]

### Step 3: Compute the Difference Matrix

Subtract the corresponding elements of matrices [tex]\(A\)[/tex] and [tex]\(B\)[/tex]:

[tex]\[ A - B = \left[\begin{array}{cc} 2 - 9 & 1 - (-67) \\ 3 - 1 & -4 - (-2) \end{array}\right] = \left[\begin{array}{cc} -7 & 68 \\ 2 & -2 \end{array}\right]. \][/tex]

So, the difference matrix is:

[tex]\[ A - B = \left[\begin{array}{cc} -7 & 68 \\ 2 & -2 \end{array}\right]. \][/tex]

### Step 4: Solve for [tex]\(X\)[/tex]

We have the equation:
[tex]\[ 3X = \left[\begin{array}{cc} -7 & 68 \\ 2 & -2 \end{array}\right]. \][/tex]

To solve for [tex]\(X\)[/tex], we divide each element of the resulting matrix [tex]\(A - B\)[/tex] by 3:

[tex]\[ X = \frac{1}{3} \left[\begin{array}{cc} -7 & 68 \\ 2 & -2 \end{array}\right] = \left[\begin{array}{cc} \frac{-7}{3} & \frac{68}{3} \\ \frac{2}{3} & \frac{-2}{3} \end{array}\right]. \][/tex]

Simplify the elements:

[tex]\[ X = \left[\begin{array}{cc} -2.33333333 & 22.66666667 \\ 0.66666667 & -0.66666667 \end{array}\right]. \][/tex]

Thus, the unknown matrix [tex]\(X\)[/tex] is:

[tex]\[ X = \left[\begin{array}{cc} -2.33333333 & 22.66666667 \\ 0.66666667 & -0.66666667 \end{array}\right]. \][/tex]

### Final Answer

The difference matrix is:
[tex]\[ \left[\begin{array}{cc} -7 & 68 \\ 2 & -2 \end{array}\right], \][/tex]

and the unknown matrix [tex]\(X\)[/tex] is:
[tex]\[ \left[\begin{array}{cc} -2.33333333 & 22.66666667 \\ 0.66666667 & -0.66666667 \end{array}\right]. \][/tex]