Can someone please help me

Mathematics

1 answer:

lorasvet [3.4K]2 years ago

6 0

The matrix expressions are:

$\left[\begin{array}{cc}12&7\\5&3\end{array}\right] * \left[\begin{array}{cc}-15&-17\\26&29\end{array}\right] = \left[\begin{array}{cc}2&-1\\3&2\end{array}\right]$
Matrix 2 cannot be solved
$\left[\begin{array}{cc}-2&3\\-4&5\end{array}\right] * \left[\begin{array}{c}3&4\end{array}\right] = \left[\begin{array}{c}6&8\end{array}\right]$

<h3>How to solve the matrix expression?</h3>

The rule for matrix product states that:

If the dimensions of matrix A is m by n, and the dimension of matrix B is n by p.

Then, the dimension of the product matrix is: m by p

Using the above rule, we have:

<u>Expression 1:</u>

$\left[\begin{array}{cc}12&7\\5&3\end{array}\right] * \left[\begin{array}{cc}a&b\\c&d\end{array}\right] = \left[\begin{array}{cc}2&-1\\3&2\end{array}\right]$

Expand:

$\left[\begin{array}{cc}12a + 7c&12b + 7d\\5a + 3c &5b + 3d\end{array}\right] = \left[\begin{array}{cc}2&-1\\3&2\end{array}\right]$

By comparison, we have:

12a + 7c = 2

5a + 3c = 3

12b+ 7d = -1

5b + 3d = 2

Using a graphing tool, we have:

a = -15, b = -17, c = 26 and d = 29

Hence, the matrix expression is:

$\left[\begin{array}{cc}12&7\\5&3\end{array}\right] * \left[\begin{array}{cc}-15&-17\\26&29\end{array}\right] = \left[\begin{array}{cc}2&-1\\3&2\end{array}\right]$

<u>Expression 2:</u>

$\left[\begin{array}{cc}6.75&3\\-9&-4\end{array}\right] * \left[\begin{array}{c}a&b\end{array}\right] = \left[\begin{array}{c}8&5\end{array}\right]$