document.write( "Question 66146: Please help with this problem that is through a practice CD class. I know that it's probably not as hard as I'm making it.\r
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document.write( "Solve for X and Y in the following problems and show your work:\r
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document.write( "a. X + Y = 6; 2X + Y = 8
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document.write( "b. 7X + 3Y = 14; 5X + 9Y = 10
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document.write( "c. 4X + Y = 16; 2X + 3Y = 24
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document.write( "d. 12X + Y = 25; 8X - 2Y = 14\r
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document.write( "I appreciate your help. \n" );
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Algebra.Com's Answer #46914 by checkley71(8403)![]() ![]() ![]() You can put this solution on YOUR website! X+Y=6 & 2X+Y=8 THEN X=6-Y FROM THE FIRST EQUATION. NOW SUBSTITUTE (6-Y) FOR X IN THE SECOND EQUATION THUS: \n" ); document.write( "2(6-Y)+Y=8 & SOLVE FOR Y THUS: \n" ); document.write( "12-2Y+Y=8 COMBINE THE Xs & SUBTRACT 12 FROM BOTH SIDES \n" ); document.write( "-Y=8-12 \n" ); document.write( "-Y=-4 DIVIDE BOTH SIDES BY -1 \n" ); document.write( "Y=4 SOLUTION. NOW SUBSTITUTE 4 FOR X IN EITHER EQUATION THUS: \n" ); document.write( "2X+4=8 \n" ); document.write( "2X=8-4 \n" ); document.write( "2X=4 \n" ); document.write( "X=4/2 \n" ); document.write( "X=2 SOLUTION \n" ); document.write( "PROOF \n" ); document.write( "X+Y=6 \n" ); document.write( "2+4=6 \n" ); document.write( "6=6 \n" ); document.write( "__________________________________________________________\r \n" ); document.write( "\n" ); document.write( "7X+3Y=14 & 5X+9Y=10 MULTIPLY THE FIRST EQUATION BY -3 TO ELIMINATE THE Ys & ADD THEM \n" ); document.write( "-21X-9Y=-42 \n" ); document.write( "5X+9Y=10 \n" ); document.write( "------------------------ \n" ); document.write( "-16X=-32 \n" ); document.write( "X=-32/-16 \n" ); document.write( "X=2 SOLUTION NOW SUBSTITUTE 2 FOR X IN EITHER EQUATION & SOLVE FOR Y \n" ); document.write( "5*2+9Y=10 \n" ); document.write( "10+9Y=10 \n" ); document.write( "9Y=10-10 \n" ); document.write( "9Y=0 \n" ); document.write( "Y=0/9 \n" ); document.write( "Y=0 \n" ); document.write( "PROOF \n" ); document.write( "7*2+3*0=14 \n" ); document.write( "14=14 \n" ); document.write( "---------------------------------------------------- \n" ); document.write( "4X+Y=16 & 2X+3Y=24 MULTIPLY THE FIRST EQUATION BY -3 & ADD TO ELIMINATE THE Ys. \n" ); document.write( "-12X-3Y=-48 \n" ); document.write( "2X+3Y=24 \n" ); document.write( "----------------------------- \n" ); document.write( "-10X=-24 \n" ); document.write( "X=-24/-10 \n" ); document.write( "X=2.4 SOLUTION. NOW SUBSTITUTE 2.4 FOR X & SOLVE FOR Y \n" ); document.write( "4*2.4+Y=16 \n" ); document.write( "9.6+Y=16 \n" ); document.write( "Y=16-9.6 \n" ); document.write( "Y=6.4 SOLUTION. \n" ); document.write( "PROOF \n" ); document.write( "2*2.4+3*6.4=24 \n" ); document.write( "4.8+19.2=24 \n" ); document.write( "24=24 \n" ); document.write( "------------------------------------------------------ \n" ); document.write( "12X+Y=25 & 8X-2Y=14 MULTIPLY THE FIRST EQUATION BY 2 & ADD \n" ); document.write( "24X+2Y=50 \n" ); document.write( "8X-2Y=14 \n" ); document.write( "----------------- \n" ); document.write( "32X=64 \n" ); document.write( "X=64/32 \n" ); document.write( "X=23 SOLUTION NOW SUBSTITUTE 2 FOR X AND SOLCVE FOR Y \n" ); document.write( "8*2-2Y=14 \n" ); document.write( "16-2Y=14 \n" ); document.write( "-2Y=14-16 \n" ); document.write( "-2Y=-2 \n" ); document.write( "T=-2/-2 \n" ); document.write( "Y=1 SOLUTION \n" ); document.write( "PROOF \n" ); document.write( "12*2+1=25 \n" ); document.write( "24+1=25 \n" ); document.write( "25=25\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( " \n" ); document.write( " |