Question 594421
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You only get to ask two questions.  So the others were deleted:
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1. What is the formula for the determinant of a 3 x 3 matrix ?
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{{{abs(matrix(3,3,a,b,c,d,e,f,g,h,i))}}} = aei + bfg + cdh - ceg - bdi - afh 
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2. Solve the inequality |2x &#8722; 4| < 10. Write the solution in interval notation and graph it:
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To remove absolute value bars with < or <u><</u>, write

                              -10 < 2x - 4 < 10, and solve for x in the middle:
Add 4 to all three sides       +4       +4   +4                           
                              ------------------
                               -6 < 2x     < 14

Divide all three sides by 2    -3 <  x     <  7

Here is the graph:

                    -----------o=============================o------------
                    -6  -5 -4 -3 -2 -1  0  1  2  3  4  5  6  7  8  9 10 11

Here is the interval notation, which is an abbreviation for the graph:

                                     (-3,7)
     
Edwin</pre>