document.write( "Question 1014596: Solve:
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document.write( " x-6y-2z=-8
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document.write( "-x+5y+3z=2
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document.write( "3x-2y-4z=18
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document.write( "
Algebra.Com's Answer #630920 by addingup(3677)![]() ![]() You can put this solution on YOUR website! x-6y-2z=-8 \n" ); document.write( "-x+5y+3z=2 \n" ); document.write( "3x-2y-4z=18 \n" ); document.write( "~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ \n" ); document.write( "x-6y-2z=-8 \n" ); document.write( "-x+5y+3z=2 \n" ); document.write( "---------- \n" ); document.write( " -y+z= -6 \n" ); document.write( "~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ \n" ); document.write( "x-6y-2z=-8 \n" ); document.write( "3x-2y-4z=18 \n" ); document.write( "On the first equation multiply all terms by -3: \n" ); document.write( "-3x+18y+6z= 24 \n" ); document.write( "Add the equations: \n" ); document.write( "-3x+18y+6z= 24 \n" ); document.write( "3x-2y-4z= 18 \n" ); document.write( "--------------- \n" ); document.write( "16y+2z= 42 \n" ); document.write( "Now we have two new equations: \n" ); document.write( "-y+z= -6 \n" ); document.write( "16y+2z= 42 \n" ); document.write( "Multiply the 1st equation times -2 \n" ); document.write( "2y-2z= 12 \n" ); document.write( "Add equations \n" ); document.write( "16y+2z= 42 \n" ); document.write( "2y-2z= 12 \n" ); document.write( "18y= 54 Divide both sides by 18 \n" ); document.write( "y= 3 Now we know the value of y. \n" ); document.write( "Take one of the last two equations and find z: \n" ); document.write( "16y+2z= 42 \n" ); document.write( "16(3)+2z= 42 \n" ); document.write( "48+2z= 42 \n" ); document.write( "2z= -6 \n" ); document.write( "z= -3 \n" ); document.write( "You say, what if I chose the other equation to find z? Well: \n" ); document.write( "2y-2z= 12 \n" ); document.write( "2(3)-2z= 12 \n" ); document.write( "6-2z= 12 \n" ); document.write( "-2z= 6 \n" ); document.write( "z= -3 Same answer. Cool, no? \n" ); document.write( "Now we know y and z, let's go back to one of the original equations to find x: \n" ); document.write( "x-6y-2z=-8 \n" ); document.write( "x-6(3)-2(-3)= -8 \n" ); document.write( "x-18+6= -8 \n" ); document.write( "x-12= -8 \n" ); document.write( "x= 4 \n" ); document.write( "~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ \n" ); document.write( "Am I right? Let's check: \n" ); document.write( "x-6y-2z=-8; 4-6(3)-2(-3)= -8; 4-18+6= 8; -18+10= -8 Correct \n" ); document.write( "-x+5y+3z=2; -4+5(3)+3(-3)= 2; -4+15-9= 2; 11-9= 2 correct \n" ); document.write( "3x-2y-4z=18; 3(4)-2(3)-4(-3)= 18; 12-6+12= 18; 6+12= 18 Correct \n" ); document.write( "We have the correct answers. \n" ); document.write( "J\r \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |