document.write( "Question 149204: x+2y=10\r
\n" ); document.write( "\n" ); document.write( "4x+5y=31\r
\n" ); document.write( "\n" ); document.write( "i need to kno what x and y equal..
\n" ); document.write( "I dont understand HOW to do this..
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Algebra.Com's Answer #115065 by Alan3354(69443)\"\" \"About 
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x+2y=10 eqn 1
\n" ); document.write( "4x+5y=31 eqn 2
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\n" ); document.write( "There are several ways to do this. In this case, the best approach might be substitution, meaning you substitute for one of the variables (x or y).\r
\n" ); document.write( "\n" ); document.write( "Since eqn 1 has an x term, solve it for x in terms of y.
\n" ); document.write( "x = 10-2y (from eqn 1)
\n" ); document.write( "Then, sub for x in eqn 2
\n" ); document.write( "4x+5y=31 eqn 2
\n" ); document.write( "4*(10-2y) + 5y = 31
\n" ); document.write( "Now there's one eqn in 1 unknown, so solve for y
\n" ); document.write( "4*(10-2y) + 5y = 31
\n" ); document.write( "40-8y + 5y = 31
\n" ); document.write( "40 - 3y = 31
\n" ); document.write( "y = 3
\n" ); document.write( "----
\n" ); document.write( "Now sub 3 for y in either eqn.
\n" ); document.write( "x+2y=10 eqn 1
\n" ); document.write( "x + 2*(3) = 10
\n" ); document.write( "x + 6 = 10
\n" ); document.write( "x = 4\r
\n" ); document.write( "\n" ); document.write( "Check by putting the values in both eqns, and it works.
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