document.write( "Question 207711: Solve for X, Y, and Z in the following systems of three equations using either substition or elimination methods:
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document.write( "a. X + 2Y + Z = 6
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document.write( " X + Y = 4
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document.write( " 3X + Y + Z = 8\r
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document.write( "b. 10X + Y + Z = 12
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document.write( " 8X + 2Y +Z = 11
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document.write( " 20X - 10Y - 2Z = 8\r
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document.write( "c. 22X + 5Y + 7Z = 12
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document.write( " 10X + 3Y + 2Z = 5
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document.write( " 9X + 2Y + 12Z = 14
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document.write( "
Algebra.Com's Answer #157383 by pjalgeb(9)![]() ![]() ![]() 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 --> \n" ); document.write( " X + Y = 4 --> \n" ); document.write( " 3X + Y + Z = 8 --> \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 \n" ); document.write( "X + Y = 4 \n" ); document.write( " Y = 4-X --> \n" ); document.write( "\n" ); document.write( "MULTIPLY \n" ); document.write( "\n" ); document.write( " -X -2Y - Z = -6 --> \n" ); document.write( "\n" ); document.write( "ADD \n" ); document.write( "\n" ); document.write( " -X -2Y - Z = -6 --> \n" ); document.write( " 3X + Y + Z = 8 --> \n" ); document.write( " _______________ \n" ); document.write( " 2X -Y = 2 \r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " 2X -Y = 2 --> \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "NOW WE CAN SOLVE FOR \n" ); document.write( "\n" ); document.write( " 2X -Y = 2 --> \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( " \n" ); document.write( "\n" ); document.write( "NOW THAT WE HAVE \n" ); document.write( "\n" ); document.write( " X + Y = 4 --> \n" ); document.write( " 2 + Y = 4 \n" ); document.write( " Y = 4-2 \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "NOW THAT WE HAVE \n" ); document.write( "\n" ); document.write( " X + 2Y + Z = 6 --> \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( " \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( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \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 --> \n" ); document.write( " 8X + 2Y + Z = 11 --> \n" ); document.write( " 20X - 10Y - 2Z = 8 --> \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 \n" ); document.write( "\n" ); document.write( " -10X - Y -Z = -12 --> \n" ); document.write( " 8X +2Y +Z = 11 --> \n" ); document.write( " _________________ \n" ); document.write( " -2X + Y = -1\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " -2X + Y = -1 --> \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "FROM \n" ); document.write( "\n" ); document.write( " -2X + Y = -1 --> \n" ); document.write( " Y = 2X-1 --> \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "NOW MULTIPLY \n" ); document.write( "\n" ); document.write( " 16X + 4Y + 2Z = 22 --> \n" ); document.write( " 20X - 10Y - 2Z = 8 --> \n" ); document.write( " ___________________ \n" ); document.write( " 36X - 6Y = 30 \n" ); document.write( " \n" ); document.write( " 36X - 6Y = 30 --> \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "NOW WE CAN SOLVE FOR \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " 36X - 6Y = 30 --> \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( " \n" ); document.write( "\n" ); document.write( "NOW THAT HAVE HAVE \n" ); document.write( "\n" ); document.write( " Y = 2X -1 --> \n" ); document.write( " Y = 2(1)-1 \n" ); document.write( " Y = 2 - 1 \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "NOW THAT HAVE HAVE \n" ); document.write( "\n" ); document.write( " 10X + Y + Z = 12 --> \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( " \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( " \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( "\n" ); document.write( "PROBLEM C \r \n" ); document.write( "\n" ); document.write( "GIVEN:\r \n" ); document.write( "\n" ); document.write( "22X + 5Y + 7Z = 12 --> \n" ); document.write( "10X + 3Y + 2Z = 5 --> \n" ); document.write( " 9X + 2Y + 12Z = 14 --> \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 \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " -22X - 5Y - 7Z = -12 --> \n" ); document.write( " 10X + 3Y + 2Z = 5 --> \n" ); document.write( " 9X + 2Y + 12Z = 14 --> \n" ); document.write( " ____________________ \n" ); document.write( " -3X + 7Z = 7\r \n" ); document.write( "\n" ); document.write( " -3X + 7Z = 7 --> \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "FROM \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " -3X + 7Z = 7 --> \n" ); document.write( " 3X = 7Z - 7 \n" ); document.write( " X = (7Z -7)/3 --> \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "MULTIPLY \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " -(27/2)x - 3Y - 18z = -21 --> \n" ); document.write( " 10X + 3Y + 2Z = 5 --> \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 --> \n" ); document.write( "\n" ); document.write( "FROM \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " [(-7/2)x - 16z = -16] * 2 --> \n" ); document.write( " -7X - 32Z = -32 --> \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "NOW WE CAN SOLVE FOR \n" ); document.write( "\n" ); document.write( " 7X - 32Z = -32 --> \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( " \n" ); document.write( "\n" ); document.write( "NOW THAT WE HAVE \n" ); document.write( "\n" ); document.write( " X = (7Z -7)/3 --> \n" ); document.write( " X = [7(1) - 7]/3 \n" ); document.write( " X = (7-7)/3 \n" ); document.write( " X = 0/3 \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "NOW THAT HAVE HAVE \n" ); document.write( "\n" ); document.write( " 22X + 5Y + 7Z = 12 --> \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( " \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( "\n" ); 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