document.write( "Question 491115: solve by the substitution method.
\n" ); document.write( "7x+4y= -1
\n" ); document.write( "-5x+y=20 \n" ); document.write( "

Algebra.Com's Answer #334525 by mananth(16946) $\"\"$ $\"About$

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7 x + 4 y = -1 .............1
\n" ); document.write( "1 y = 20 + 5 x ---------2
\n" ); document.write( "/ 1 =
\n" ); document.write( " y = 20 + 5 x
\n" ); document.write( "Substitute y in (1)
\n" ); document.write( "7 x + 4 ( 20 + 5 x ) = -1
\n" ); document.write( "7 x + 80 + 20 x = -1
\n" ); document.write( "7 x + 20 x = -1 -80
\n" ); document.write( "27 x = -81
\n" ); document.write( "/ 27
\n" ); document.write( "x= -3
\n" ); document.write( "Plug the value of x in (1)
\n" ); document.write( "7 x + 4 y = -1
\n" ); document.write( "7 * -3 + 4 y = -1
\n" ); document.write( "-21 + 4 y = -1
\n" ); document.write( "4 y = 20
\n" ); document.write( "/ 4
\n" ); document.write( "y= 5
\n" ); document.write( "m.ananth@hotmail.ca
\n" ); document.write( " \n" ); document.write( "

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