Question 1027619
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I just answered in <A HREF=https://www.algebra.com/algebra/college/linear/Linear_Algebra.faq.question.1027622.html>https://www.algebra.com/algebra/college/linear/Linear_Algebra.faq.question.1027622.html</A> 


but you submitted the same post again.


So, I make a conclusion that you want to know the procedure and details.


If you would be so hard-working student as I was in my student years, you simply multiply this 3x3 matrix two times and get the answer.


But contemporary students are different . . . 


Even in this situation you could find the (right ?) exit. 
Find the internet site with key words "multiply 3x3 matrix online for free" and choose the most appropriate.


For example, I found this:
<A HREF=https://www.easycalculation.com/matrix/matrix-multiplication.php>https://www.easycalculation.com/matrix/matrix-multiplication.php</A>