document.write( "Question 1132726: how do you solve the system of equations using substitution?
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Algebra.Com's Answer #749849 by ikleyn(52803) $\"\"$ $\"About$

You can put this solution on YOUR website!
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\n" ); document.write( "\n" ); document.write( " It can be done in much simpler way, and you deserve to know it . . . \r
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document.write( "From the first equation, you just have the expression for 3y: it is -7x + 10.\r\n" );
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document.write( "Substitute it into the second equation in whole, as is, replacing 3y in its left side by -7x + 10.\r\n" );
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document.write( "You will get\r\n" );
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document.write( "   -7x + 10 = 4x + 38.   (*)\r\n" );
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document.write( "It is how the substitution method works in this case (or, it is the way on how YOU CAN USE the substitution method in this case).\r\n" );
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document.write( "So, you MOMENTARILY obtain a single equation for one unknown x, which you easily can solve.  From (*), you have\r\n" );
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document.write( "    10 - 38 = 4x + 7x\r\n" );
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document.write( "    -28 = 11x  ====>  x = .\r\n" );
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document.write( "As the next and last step, you substitute the found value of x into either of the two given equations to determine y.\r\n" );
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document.write( "    3y =  =  =   ====>  y =  = .\r\n" );
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document.write( "ANSWER.  x = ,  y = .\r\n" );
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\n" ); document.write( "\n" ); document.write( "Solved // by using the substitution method // in its economic mode.\r
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\n" ); document.write( "\n" ); document.write( "For other similar solved problems, see the lesson\r
\n" ); document.write( "\n" ); document.write( " - Useful tricks when solving systems of 2 equations in 2 unknowns by the Substitution method \r
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