Algebra.Com's Answer #119159 by Edwin McCravy(20056)![\"\"](\"/images/stars/stars-13.gif\")  
You can put this solution on YOUR website!
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document.write( "I need to find the product of the two matrices. I know they look a little funny,im not sure how to get them set up right. The first one is a (3X3) and the second a (3x3), so i know it is defined, and the product is able to be found. I can do addiction,but im completly confused by multiplication. Id love to see the step and the correct answer. I really appericate your help!\r
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document.write( "How do you multiply all of these numbers????
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document.write( "The first matrix has dimensions 3 down by 3 across.\r\n" );
document.write( "That's a 3x3 matrix. \r\n" );
document.write( "The second matrix has dimensions 3 down by 3 across. \r\n" );
document.write( "That's a 3x3 matrix.\r\n" );
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document.write( "Write 3x3 3x3\r\n" );
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document.write( "The two (blue) inner dimensions are both 3. They must be the same\r\n" );
document.write( "in order for the matrices to even be multipliable. If they weren't the\r\n" );
document.write( "same, the multiplication would not be defined. Since they are both\r\n" );
document.write( "3, they can be multiplied. The product matrix will have the two outer\r\n" );
document.write( "(red) dimensions. They are both 3, so the product matrix will also be\r\n" );
document.write( "a 3x3 matrix.\r\n" );
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document.write( "Set the product equal to a 3x3 matrix of blanks to\r\n" );
document.write( "fill in.\r\n" );
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document.write( "I won't go through all 9 blanks. I will only tell you how to fill in\r\n" );
document.write( "three of them at random. Then you will know how to do the rest.\r\n" );
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document.write( "Let's fill in the blank which is in row 3 and column 2,\r\n" );
document.write( "that's in the middle of the bottom row:\r\n" );
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document.write( "Take row 3 from the first matrix:\r\n" );
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document.write( "and column 2 of the second matrix:\r\n" );
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document.write( "Multiply corresponding elements then add them all:\r\n" );
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document.write( "So put a  in the blank in row 3 and column 2:\r\n" );
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document.write( "Next let's fill in the blank in the upper right hand corner.\r\n" );
document.write( "That is the blank in row 1 and in column 3:\r\n" );
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document.write( "Take row 1 from the first matrix:\r\n" );
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document.write( "and column 3 from the second matrix:\r\n" );
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document.write( "Multiply corresponding elements then add them all:\r\n" );
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document.write( "So put a  in the blank in row 1 and column 3,\r\n" );
document.write( "that is, the upper right corner:\r\n" );
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document.write( "----\r\n" );
document.write( "One more!\r\n" );
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document.write( "Let's fill in the blank in row 2 and column 1:\r\n" );
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document.write( "Take row 2 from the first matrix:\r\n" );
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document.write( "and column 1 of the second matrix:\r\n" );
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document.write( "Multiply corresponding elements then add them all:\r\n" );
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document.write( "So put a  in the blank in row 2 and column 1:\r\n" );
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document.write( "Do you see how to do it now? To fill in any blank in the \r\n" );
document.write( "product matrix, you decide which row and column the blank\r\n" );
document.write( "is in which you want to fill, then get the corresponding \r\n" );
document.write( "row from the first matrix, and the corresponding column \r\n" );
document.write( "from the second matrix, then multiply corresponding elements \r\n" );
document.write( "and add them. You can fill them in in any order you choose.\r\n" );
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document.write( "When you fill in the rest of the blanks you should have this:\r\n" );
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document.write( "Edwin
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