Question 1194065
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Refer to this page
<a href = "https://www.chilimath.com/lessons/advanced-algebra/determinant-3x3-matrix/">https://www.chilimath.com/lessons/advanced-algebra/determinant-3x3-matrix/</a>
For a lesson on how 3x3 determinants work


Following the template mentioned on that page, we would have these steps:
<img width="60%" src = "https://i.imgur.com/8EuYFJY.png">
This means
-40x-4 = 716
I'll let you take over to finish solving for x.


Tip: 
You can use GeoGebra's CAS feature to verify the determinant is equal to -40x-4
CAS stands for Computer Algebra System
I typed this in for the input
<font color=blue>Determinant({{2,3x,-2},{0,-2,-2},{6,5,x}})</font>
You must be in the CAS mode or else the calculation won't work. This is due to the presence of the variable x.
See this link here
<a href = "https://www.geogebra.org/calculator/gsdw7jqg">https://www.geogebra.org/calculator/gsdw7jqg</a>
Once you determine the numeric value of x, you can switch back to regular calculator mode. Though you could stick to CAS as well.


Extra side note:
The determinant of the 2x2 matrix {{{(matrix(2,2,a,b,c,d))}}} is {{{ad - bc}}}
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