document.write( "Question 208211: SOLVE USING DETERMINANTS and CRAMER'S RULE\r
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document.write( "Three kilos of homegrown tobacco and 8 kilos of imported tobacco cost $39.70 ,and 5 kilos of homegrown tobacco and 6 kilos of imported tobacco cost $47.10. What is the cost per kilo for both kinds of tobacco? \n" );
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Algebra.Com's Answer #157514 by pjalgeb(9) ![]() You can put this solution on YOUR website! REQUIRED: Find y(price of homegrown tobacco) and x(price of imported tobacco)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "SOLUTION:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " Amount HGT Amount of IMPT IMPT Price HGT Price Total Price \n" ); document.write( " (kilos) (kilos) ($ per kilo) ($ per kilo) ($)\r \n" ); document.write( "\n" ); document.write( " ______________________________________________________________________________\r \n" ); document.write( "\n" ); document.write( "First Order | 3 : 8 : x : y : 3x+8y = 39.7 |\r \n" ); document.write( "\n" ); document.write( "Second Order | 5 : 6 : x : y : 5x+6y = 47.1 | \n" ); document.write( " ______________________________________________________________________________\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "The following Equations can be derived from the total price column:\r \n" ); document.write( "\n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "Now we have two equations with two unknowns:\r \n" ); document.write( "\n" ); document.write( " 3x+8y = 39.7 --> Equation 1 \n" ); document.write( " 5x+6y = 47.1 --> Equation 2\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "The augmented 2x2 matrix for the above system of equations is:\r \n" ); document.write( "\n" ); document.write( " | 3 8 | 39.7 | \n" ); document.write( " | 5 6 | 47.1 |\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Using Cramer's Rule:\r \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "First we solve for D, Dx and Dy:\r \n" ); document.write( "\n" ); document.write( "D = | 3 8 | = 3(6) - 8(5) = 18 - 40 = - 22 \n" ); document.write( " | 5 6 |\r \n" ); document.write( "\n" ); document.write( "since D is not 0 then we can proceed:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Dx = | 39.7 8 | = 39.7(6) -8(47.1) = 238.2 - 376.8 = -138.6 \n" ); document.write( " | 47.1 6 | \r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Dy = | 3 39.7 | = 3(47.1) - 5(39.7) = 141.3 - 198.5 = -57.2 \n" ); document.write( " | 5 47.1 | \r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Now we can solve for x and y:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "ANSWER:\r \n" ); document.write( "\n" ); document.write( "Homegrown tobacco costs $2.60 per kilo while the imported ones costs $6.30 per kilo.\r \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |