document.write( "Question 207711: Solve for X, Y, and Z in the following systems of three equations using either substition or elimination methods:
\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( "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( "c. 22X + 5Y + 7Z = 12
\n" ); document.write( " 10X + 3Y + 2Z = 5
\n" ); document.write( " 9X + 2Y + 12Z = 14
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Algebra.Com's Answer #157383 by pjalgeb(9)\"\" \"About 
You can put this solution on YOUR website!

\n" ); document.write( "PROBLEM A\r
\n" ); document.write( "\n" ); document.write( "GIVEN:
\n" ); document.write( " X + 2Y + Z = 6 --> \"Equation+1\"
\n" ); document.write( " X + Y = 4 --> \"Equation+2\"
\n" ); document.write( " 3X + Y + Z = 8 --> \"Equation+3\"\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "REQUIRED: FIND X, Y AND Z\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "SOLUTION:
\n" ); document.write( "FROM \"Equation+2\":
\n" ); document.write( "X + Y = 4
\n" ); document.write( " Y = 4-X --> \"Equation+4\"\r
\n" ); document.write( "\n" ); document.write( "MULTIPLY \"Equation+1\" WITH -1 AND ADD TO \"Equation+3\" TO ELIMINATE \"Z\":\r
\n" ); document.write( "\n" ); document.write( " -X -2Y - Z = -6 --> \"Equation+5\"\r
\n" ); document.write( "\n" ); document.write( "ADD \"Equation+5\" AND \"Equation+3\":\r
\n" ); document.write( "\n" ); document.write( " -X -2Y - Z = -6 --> \"Equation+5\"
\n" ); document.write( " 3X + Y + Z = 8 --> \"Equation+3\"
\n" ); document.write( " _______________
\n" ); document.write( " 2X -Y = 2 \r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " 2X -Y = 2 --> \"Equation+6\"\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "NOW WE CAN SOLVE FOR \"X\" USING \"Equation+4\" AND \"Equation+6\" BY SUBSTITUTION:\r
\n" ); document.write( "\n" ); document.write( " 2X -Y = 2 --> \"Equation+6\"
\n" ); document.write( " 2X -(4-X) = 2
\n" ); document.write( " 2X -4 + X = 2
\n" ); document.write( " 3X = 2 + 4
\n" ); document.write( " 3X = 6
\n" ); document.write( " X = 6/3
\n" ); document.write( " \"X+=+2\"\r
\n" ); document.write( "\n" ); document.write( "NOW THAT WE HAVE \"X\", WE CAN SOLVE FOR \"Y\" USING \"Equation+2\" AND \"X=2\" BY SUBSTITUTION: \r
\n" ); document.write( "\n" ); document.write( " X + Y = 4 --> \"Equation+2\"
\n" ); document.write( " 2 + Y = 4
\n" ); document.write( " Y = 4-2
\n" ); document.write( " \"Y+=+2\"\r
\n" ); document.write( "\n" ); document.write( "NOW THAT WE HAVE \"x\" AND \"Y\", WE CAN SOLVE FOR \"Z\" USING \"Equation+1\" BY SUBSTITUTION:\r
\n" ); document.write( "\n" ); document.write( " X + 2Y + Z = 6 --> \"Equation+1\"
\n" ); document.write( " 2 + 2(2) + Z = 6
\n" ); document.write( " 2 + 4 + Z = 6
\n" ); document.write( " 6 + Z = 6
\n" ); document.write( " Z = 6-6
\n" ); document.write( " \"Z+=+0\"\r
\n" ); document.write( "\n" ); document.write( "\"ANSWER+TO+PROBLEM+A\" \r
\n" ); document.write( "\n" ); document.write( "\"X+=+2\"
\n" ); document.write( "\"Y+=+2\"
\n" ); document.write( "\"Z+=+O\"\r
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\n" ); document.write( "\n" ); document.write( "PROBLEM B.\r
\n" ); document.write( "\n" ); document.write( "GIVEN:\r
\n" ); document.write( "\n" ); document.write( " 10X + Y + Z = 12 --> \"Equation+1\"
\n" ); document.write( " 8X + 2Y + Z = 11 --> \"Equation+2\"
\n" ); document.write( " 20X - 10Y - 2Z = 8 --> \"Equation+3\"\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "REQUIRED: FIND X, Y AND Z\r
\n" ); document.write( "\n" ); document.write( "
\n" ); document.write( "SOLUTION:
\n" ); document.write( "MULTIPLY \"Equation+1\" WITH -1 AND ADD TO \"Equation+2\" TO ELIMINATE \"Z\":\r
\n" ); document.write( "\n" ); document.write( " -10X - Y -Z = -12 --> \"Equation+1\"*(-1)
\n" ); document.write( " 8X +2Y +Z = 11 --> \"Equation+2\"
\n" ); document.write( " _________________
\n" ); document.write( " -2X + Y = -1\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " -2X + Y = -1 --> \"Equation+4\"\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "FROM \"Equation+4\":\r
\n" ); document.write( "\n" ); document.write( " -2X + Y = -1 --> \"Equation+4\"
\n" ); document.write( " Y = 2X-1 --> \"Equation+5\"\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "NOW MULTIPLY \"Equation+2\" WITH \"2\" AND ADD TO \"Equation+3\" TO ELIMINATE \"Z\":\r
\n" ); document.write( "\n" ); document.write( " 16X + 4Y + 2Z = 22 --> \"Equation+2\"*(2)
\n" ); document.write( " 20X - 10Y - 2Z = 8 --> \"Equation+3\"
\n" ); document.write( " ___________________
\n" ); document.write( " 36X - 6Y = 30
\n" ); document.write( "
\n" ); document.write( " 36X - 6Y = 30 --> \"Equation+6\"\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "NOW WE CAN SOLVE FOR \"X\" USING \"Equation+5\" IN \"Equation+6\":\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " 36X - 6Y = 30 --> \"Equation+6\"
\n" ); document.write( " 36X - 6(2X-1) = 30
\n" ); document.write( " 36X -12X + 6 = 30
\n" ); document.write( " 24X = 30-6
\n" ); document.write( " 24X = 24
\n" ); document.write( " X = 24/24
\n" ); document.write( " \"X+=+1\"\r
\n" ); document.write( "\n" ); document.write( "NOW THAT HAVE HAVE \"X\", WE CAN SOLVE FOR \"Y\" USING \"Equation+5\":\r
\n" ); document.write( "\n" ); document.write( " Y = 2X -1 --> \"Equation+5\"
\n" ); document.write( " Y = 2(1)-1
\n" ); document.write( " Y = 2 - 1
\n" ); document.write( " \"Y+=+1\"\r
\n" ); document.write( "\n" ); document.write( "NOW THAT HAVE HAVE \"X\" AND \"Y\", WE CAN SOLVE FOR \"Z\" USING \"Equation+1\", \"Equation+2\" OR \"Equation+%0D%0A%0D%0A3\", LETS TRY \"Equation+1\":\r
\n" ); document.write( "\n" ); document.write( " 10X + Y + Z = 12 --> \"Equation+1\"
\n" ); document.write( " 10(1) + 1 + Z = 12
\n" ); document.write( " 10 + 1 + Z = 12
\n" ); document.write( " 11 + Z = 12
\n" ); document.write( " Z = 12-11
\n" ); document.write( " \"Z+=+1\"\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"ANSWER+TO+PROBLEM+B\"\r
\n" ); document.write( "\n" ); document.write( "\"X+=+1\"
\n" ); document.write( "\"Y+=+1\"
\n" ); document.write( "\"Z+=+1\"\r
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\n" ); document.write( "\n" ); document.write( "PROBLEM C \r
\n" ); document.write( "\n" ); document.write( "GIVEN:\r
\n" ); document.write( "\n" ); document.write( "22X + 5Y + 7Z = 12 --> \"Equation+1\"
\n" ); document.write( "10X + 3Y + 2Z = 5 --> \"Equation+2\"
\n" ); document.write( " 9X + 2Y + 12Z = 14 --> \"Equation+3\"\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "REQUIRED: FIND X, Y AND Z\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "SOLUTION:\r
\n" ); document.write( "\n" ); document.write( "MULTIPLY \"Equation+1\" WITH \"-1\" AND ADD TO \"Equation+2\" AND \"Equation+3\" TO ELIMINATE \"Y\":\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " -22X - 5Y - 7Z = -12 --> \"Equation+1\"*(-1)
\n" ); document.write( " 10X + 3Y + 2Z = 5 --> \"Equation+2\"
\n" ); document.write( " 9X + 2Y + 12Z = 14 --> \"Equation+3\"
\n" ); document.write( " ____________________
\n" ); document.write( " -3X + 7Z = 7\r
\n" ); document.write( "\n" ); document.write( " -3X + 7Z = 7 --> \"Equation+4\"\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "FROM \"Equation+4\":\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " -3X + 7Z = 7 --> \"Equation+4\"
\n" ); document.write( " 3X = 7Z - 7
\n" ); document.write( " X = (7Z -7)/3 --> \"Equation+5\"\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "MULTIPLY \"Equation+3\" WITH \"-%283%2F2%29\" AND ADD TO \"Equation+2\" TO ELIMINATE \"Y\":\r
\n" ); document.write( "\n" ); document.write( "
\n" ); document.write( " -(27/2)x - 3Y - 18z = -21 --> \"Equation+3\" * (-3/2)
\n" ); document.write( " 10X + 3Y + 2Z = 5 --> \"Equation+2\"
\n" ); document.write( " _________________________
\n" ); document.write( "
\n" ); document.write( " (-7/2)x - 16z = -16 \r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " (-7/2)x - 16z = -16 --> \"Equation+7\"\r
\n" ); document.write( "\n" ); document.write( "FROM \"Equation+7\":\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " [(-7/2)x - 16z = -16] * 2 --> \"Equation+7\"*2
\n" ); document.write( " -7X - 32Z = -32 --> \"Equation+8\"\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "NOW WE CAN SOLVE FOR \"X\" USING \"Equation+5\" IN \"Equation+8\":\r
\n" ); document.write( "\n" ); document.write( " 7X - 32Z = -32 --> \"Equation+8\"
\n" ); document.write( " -7[(7Z-7)/3] - 32Z = -32
\n" ); document.write( " [(-49Z + 49)/3 - 32Z = -32] *3
\n" ); document.write( " -49Z + 49 - 96Z = -96
\n" ); document.write( " -145Z = -145
\n" ); document.write( " Z = -145/-145
\n" ); document.write( " \"Z+=+1\"\r
\n" ); document.write( "\n" ); document.write( "NOW THAT WE HAVE \"Z\" WE CAN SOLVE FOR \"X\" USING \"Equation+5\":\r
\n" ); document.write( "\n" ); document.write( " X = (7Z -7)/3 --> \"Equation+5\"
\n" ); document.write( " X = [7(1) - 7]/3
\n" ); document.write( " X = (7-7)/3
\n" ); document.write( " X = 0/3
\n" ); document.write( " \"X+=+0\"\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "NOW THAT HAVE HAVE \"Z\" AND \"Y\", WE CAN SOLVE FOR \"Y\" USING \"Equation+1\", \"Equation+2\" OR \"Equation+%0D%0A%0D%0A3\", LETS TRY \"Equation+1\":\r
\n" ); document.write( "\n" ); document.write( " 22X + 5Y + 7Z = 12 --> \"Equation+1\"
\n" ); document.write( " 22(0) + 5Y + 7(1) = 12
\n" ); document.write( " 0 + 5Y + 7 = 12
\n" ); document.write( " 5Y = 12-7
\n" ); document.write( " 5Y = 5
\n" ); document.write( " Y = 5/5
\n" ); document.write( " \"Y+=+1\"\r
\n" ); document.write( "\n" ); document.write( "\"ANSWER+TO+PROBLEM+C\"\r
\n" ); document.write( "\n" ); document.write( "\"X+=+0\"
\n" ); document.write( "\"Y+=+1\"
\n" ); document.write( "\"Z+=+1\"\r
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