document.write( "Question 182376: Solve by addition method\r
\n" ); document.write( "\n" ); document.write( "3/7x + 5/9y = 27
\n" ); document.write( "1/9x + 2/7y =7 \n" ); document.write( "
Algebra.Com's Answer #136876 by stanbon(75887)\"\" \"About 
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Solve by addition method
\n" ); document.write( "3/7x + 5/9y = 27
\n" ); document.write( "1/9x + 2/7y =7
\n" ); document.write( "--------------
\n" ); document.write( "The lcm of 7 and 9 is 63.
\n" ); document.write( "Multiply thru both equations by 63 to get:
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\n" ); document.write( "27x + 35y = 63*27
\n" ); document.write( "7x + 18y = 63*7
\n" ); document.write( "--------------------------
\n" ); document.write( "Multiply thru the 1st equation by 7 and the 2nd equatio by -27 to get:\r
\n" ); document.write( "\n" ); document.write( "7*27x + 7*35y = 7*63*27
\n" ); document.write( "7*-27x+18*-27y = -27*63*7
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\n" ); document.write( "Add to solve for \"y\":
\n" ); document.write( "(7*35-18*27)y = 7*63*27 - 27*63*7
\n" ); document.write( "y = 0
\n" ); document.write( "------------------
\n" ); document.write( "Substitute into 7x + 18y = 7*63 to solve for \"x\":
\n" ); document.write( "7x = 7*63
\n" ); document.write( "x = 63
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\n" ); document.write( "Solution: x= 63 and y = 0
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\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H.
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