document.write( "Question 2240: Ok this is my last problem. That you so much!\r
\n" ); document.write( "\n" ); document.write( "Solve for X,Y,and Z in the following systems of three equations:\r
\n" ); document.write( "\n" ); document.write( "A) X+2Y+Z =6
\n" ); document.write( " X+Y=4
\n" ); document.write( " 3X+Y+Z=8\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "B) 10X+Y+Z=12
\n" ); document.write( " 8X+2Y+Z=11
\n" ); document.write( " 20X-10Y-2Z=8\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "C) 22X+5Y+7Z=12
\n" ); document.write( " 10X+3Y+2Z=5
\n" ); document.write( " 9X+2Y+12Z=14
\n" ); document.write( "

Algebra.Com's Answer #933 by DeepaEvangeline(15)\"\" \"About 
You can put this solution on YOUR website!
a)
\n" ); document.write( "X+2Y+Z=6 - (1)
\n" ); document.write( "X+Y=4 - (2)
\n" ); document.write( "3X+Y+Z=8 - (3)\r
\n" ); document.write( "\n" ); document.write( "Eqn(3) - Eqn(1) gives
\n" ); document.write( "2X-Y=2 - (4)\r
\n" ); document.write( "\n" ); document.write( "Adding Eqn(2) & (4) gives
\n" ); document.write( "3X=6 -> X = 2\r
\n" ); document.write( "\n" ); document.write( "Substituting the value of X in eqn(2) gives
\n" ); document.write( "X+Y=4
\n" ); document.write( "2+Y=4 -> Y = 2\r
\n" ); document.write( "\n" ); document.write( "Sub the value of X=2 and Y=2 in eqn (1) gives
\n" ); document.write( "2+2.2+Z=6
\n" ); document.write( "2+4+Z=6 -> Z = 0\r
\n" ); document.write( "\n" ); document.write( "X = 2, Y = 2, Z = 0\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "b)
\n" ); document.write( "10X+Y+Z=12 - (1)
\n" ); document.write( "8X+2Y+Z=11 - (2)
\n" ); document.write( "20X-10Y-2Z=8 - (3)\r
\n" ); document.write( "\n" ); document.write( "Subtracting eqn(2) from eqn(1) gives
\n" ); document.write( "2X-Y=1 - (4)\r
\n" ); document.write( "\n" ); document.write( "Eqn(2) x 2 gives
\n" ); document.write( "16X+4Y+2Z=22 - (5)\r
\n" ); document.write( "\n" ); document.write( "Eqn(3) + Eqn(5) gives
\n" ); document.write( "36X-6Y=30 - (6)\r
\n" ); document.write( "\n" ); document.write( "Eqn(4) x 6 gives
\n" ); document.write( "12X-6Y=6 - (7)\r
\n" ); document.write( "\n" ); document.write( "Eqn(6) - Eqn(7) gives
\n" ); document.write( "24X=24 => X = 1\r
\n" ); document.write( "\n" ); document.write( "Substituting X = 1 in eqn(4) gives
\n" ); document.write( "2.1-Y=1 => Y = 1\r
\n" ); document.write( "\n" ); document.write( "Sub the value of X = 1 and Y = 1 in eqn(1) gives
\n" ); document.write( "10.1 + 1 + Z = 12
\n" ); document.write( "11 + Z = 12 => Z = 1\r
\n" ); document.write( "\n" ); document.write( "X = 1, Y = 1, Z = 1\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "c)
\n" ); document.write( "22X+5Y+7Z=12 - (1)
\n" ); document.write( "10X+3Y+2Z=5 - (2)
\n" ); document.write( "9X+2Y+12Z=14 - (3)\r
\n" ); document.write( "\n" ); document.write( "Eqn(1) x 3 gives
\n" ); document.write( "66X+15Y+21Z=36 - (4)\r
\n" ); document.write( "\n" ); document.write( "Eqn(2) x 5 gives
\n" ); document.write( "50X+15Y+10Z=25 - (5)\r
\n" ); document.write( "\n" ); document.write( "Eqn(4) - eqn(5) gives
\n" ); document.write( "16X+11Z=11 - (6)\r
\n" ); document.write( "\n" ); document.write( "Eqn(2) x 2 gives
\n" ); document.write( "20X+6Y+4Z=10 - (7)\r
\n" ); document.write( "\n" ); document.write( "Eqn(3) x 3 gives
\n" ); document.write( "27X+6Y+36Z=42 - (8)\r
\n" ); document.write( "\n" ); document.write( "Eqn(8) - eqn(7) gives
\n" ); document.write( "7X+32Z=32 - (9)\r
\n" ); document.write( "\n" ); document.write( "Solving eqn(6) & (9),
\n" ); document.write( "Eqn(6) x 7 gives
\n" ); document.write( "112X+77Z=77 - (10)\r
\n" ); document.write( "\n" ); document.write( "Eqn(9) x 16 gives
\n" ); document.write( "112X+512Z=512 - (11)\r
\n" ); document.write( "\n" ); document.write( "Eqn(11) - eqn(10) gives
\n" ); document.write( "435Z=435 => Z = 1\r
\n" ); document.write( "\n" ); document.write( "Substituting Z = 1 in eqn(9) gives
\n" ); document.write( "7X+32=32 => X = 0\r
\n" ); document.write( "\n" ); document.write( "Sub X = 0 and Z = 1 in eqn(2) gives
\n" ); document.write( "10.0 + 3Y + 2.1 = 5
\n" ); document.write( "3Y = 3 => Y = 1\r
\n" ); document.write( "\n" ); document.write( "X = 0, Y = 1, Z = 1
\n" ); document.write( "
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