Answer:

Step-by-step explanation:
Notice from the attached image that -315 degrees is the same as 45 degrees.
Recall as well that the csc function is defined as the reciprocal of the sine function: 
Then, you need to evaluate 
Positive linear association !
Each element of the matrix are multiplied by the scalar to form a matrix of
same size as the original matrix in matrix scalar multiplication.
Reasons:
The matrix <em>A</em> is presented as follows;
![A = {\left[\begin{array}{ccc}4&6&8\\6&8&10\end{array}\right]}](https://tex.z-dn.net/?f=A%20%3D%20%7B%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D4%266%268%5C%5C6%268%2610%5Cend%7Barray%7D%5Cright%5D%7D)
Using the multiplication of a matrix and a scalar, we have;
![60 \cdot A = 60 \cdot \left[\begin{array}{ccc}4&6&8\\6&8&10\end{array}\right] = \left[\begin{array}{ccc}60 \times 4&60 \times 6&60 \times 8\\60 \times 6&60 \times 8&60 \times 10\end{array}\right] = \left[\begin{array}{ccc}\mathbf{240}&\mathbf{360}&\mathbf{480}\\\mathbf{360}&\mathbf{480}&\mathbf{600}\end{array}\right]](https://tex.z-dn.net/?f=60%20%5Ccdot%20A%20%3D%2060%20%5Ccdot%20%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D4%266%268%5C%5C6%268%2610%5Cend%7Barray%7D%5Cright%5D%20%3D%20%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D60%20%5Ctimes%204%2660%20%5Ctimes%206%2660%20%5Ctimes%208%5C%5C60%20%5Ctimes%206%2660%20%5Ctimes%208%2660%20%5Ctimes%2010%5Cend%7Barray%7D%5Cright%5D%20%3D%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D%5Cmathbf%7B240%7D%26%5Cmathbf%7B360%7D%26%5Cmathbf%7B480%7D%5C%5C%5Cmathbf%7B360%7D%26%5Cmathbf%7B480%7D%26%5Cmathbf%7B600%7D%5Cend%7Barray%7D%5Cright%5D)
Therefore;
![60 \cdot A = \left[\begin{array}{ccc}240\4&360&480\\360&480&600\end{array}\right]](https://tex.z-dn.net/?f=60%20%5Ccdot%20A%20%3D%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D240%5C4%26360%26480%5C%5C360%26480%26600%5Cend%7Barray%7D%5Cright%5D)
Learn more about matrices here:
brainly.com/question/14296012
Here is the equation:

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You need to get "x" by itself so minus 3 from each side

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Divide 8 by 2

÷

x=4
So each 4 is equivalent to 4
Lets check:

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So that means that Marcus practiced the piano for 4 hours and Donnel practiced for 7