document.write( "Question 475310: 2x + 4y + 4z = 16
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document.write( "2x - y + 3z = 9
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document.write( "3x + 4y - z = 8 \n" );
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Algebra.Com's Answer #325930 by ccs2011(207)![]() ![]() You can put this solution on YOUR website! I think the best way to do these is using the elimination method. \n" ); document.write( "Eliminate a variable to break it down into a system of 2 equations, then use elimination again to break it down to a single equation. Solve for that variable and then use substitution to find the 2nd variable in the system of 2 equations. Then substitute both those values into one of the original equations to find 3rd variable. \n" ); document.write( "Let me label each equation: A,B,C for reference \n" ); document.write( "A: \n" ); document.write( "B: \n" ); document.write( "C: \n" ); document.write( "Notice A and C both have a 4y, therefore it will be easiest to eliminate variable y. Multiply C by -1. Add A and C. Call the resulting equation D. \n" ); document.write( "D: \n" ); document.write( "We still need another equation with x and z. To eliminate y again. Multiply B by 4. Add A and B. Call the resulting equation E. \n" ); document.write( "E: \n" ); document.write( "Now eliminate x. Multiply D by 10. Add D and E. \n" ); document.write( " \n" ); document.write( "Solve for z. Divide by 66 on both sides. \n" ); document.write( " \n" ); document.write( "Substitute z=2 into D. \n" ); document.write( " \n" ); document.write( "Solve for x. \n" ); document.write( " \n" ); document.write( "Subtract 10 on both sides \n" ); document.write( " \n" ); document.write( "Flip signs \n" ); document.write( " \n" ); document.write( "Substitute x=2, z=2 into B. \n" ); document.write( " \n" ); document.write( "Solve for y \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "Subtract 10 on both sides \n" ); document.write( " \n" ); document.write( "Flip signs \n" ); document.write( " \n" ); document.write( "Verify solution by substituting into other equations A and C. \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "True...it works. \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "True..it works. \n" ); document.write( "Solution is x = 2, y = 1, z = 2 \n" ); document.write( " \n" ); document.write( " |