.
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document.write( "Solve the following equation for x and y:\r
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document.write( "(2)^2+x +(3)^3+y=275
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document.write( "(2)^3+x +(3)^2+y=145
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document.write( "~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\r
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document.write( "Since you do not use parentheses properly, there are several ways to read your system.\r\n" );
document.write( "Your writing is ambiguous. To avoid ambiguity, use parentheses.\r\n" );
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document.write( "Is THIS modification what you want?\r\n" );
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document.write( "
=
, (1)\r\n" );
document.write( "
=
. (2)\r\n" );
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document.write( "Below is the solution of this system.\r\n" );
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document.write( "Since
=
,
=
,
=
,
=
, you can rewrite the system (1), (2) in the form\r\n" );
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document.write( "
+
=
, (1')\r\n" );
document.write( "
+
=
. (2')\r\n" );
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document.write( "This system is still non-linear.\r\n" );
document.write( "The way to solve it is to introduce new variables u =
and v =
.\r\n" );
document.write( "Then the system (1'), (2') takes the form\r\n" );
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document.write( "4u + 27v = 275, (3)\r\n" );
document.write( "8u + 9v = 145. (4)\r\n" );
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document.write( "The system (3), (4) is just a linear, and we can easily solve it.\r\n" );
document.write( "I will use the Elimination method. Multiply equation (3) by 2 (both sides). You will get\r\n" );
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document.write( "8u + 54v = 550, (3')\r\n" );
document.write( "8u + 9v = 145. (4')\r\n" );
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document.write( "Now, distract (3') from (4'). You will get\r\n" );
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document.write( "54v - 9v = 550 - 145 ---> 45v = 405 ---> v =
= 9.\r\n" );
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document.write( "Now recall that v =
, or 9 =
. Hence, y = 2, and one unknown is just found.\r\n" );
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document.write( "Next, from (3) u =
=
=
= 8.\r\n" );
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document.write( "Again, recall that u =
, or 8 =
. Hence, x = 3.\r\n" );
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document.write( "The problem is solved.\r\n" );
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document.write( "Answer. x = 3, y = 2.\r\n" );
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document.write( "You can check that the solution is correct.\r\n" );
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