document.write( "Question 548129: solve by substitution
\n" ); document.write( "5x + 3y = 8
\n" ); document.write( "-7x + y = 20 \n" ); document.write( "

Algebra.Com's Answer #356718 by mananth(16946) $\"\"$ $\"About$

You can put this solution on YOUR website!
5 x + 3 y = 8 .............1
\n" ); document.write( "1 y = 20 + 7 x ---------2
\n" ); document.write( "/ 1 =
\n" ); document.write( " y = 20 + 7 x
\n" ); document.write( "Substitute y in (1)
\n" ); document.write( "5 x + 3 ( 20 + 7 x ) = 8
\n" ); document.write( "5 x + 60 + 21 x = 8
\n" ); document.write( "5 x + 21 x = 8 -60
\n" ); document.write( "26 x = -52
\n" ); document.write( "/ 26
\n" ); document.write( "x= -2
\n" ); document.write( "Plug the value of x in (1)
\n" ); document.write( "5 x + 3 y = 8
\n" ); document.write( "5 * -2 + 3 y = 8
\n" ); document.write( "-10 + 3 y = 8
\n" ); document.write( "3 y = 18
\n" ); document.write( "/ 3
\n" ); document.write( "y= 6
\n" ); document.write( "m.ananth@hotmail.ca
\n" ); document.write( "CHECK
\n" ); document.write( "1 y = 20 + 7 x
\n" ); document.write( "6 = 20 + -14
\n" ); document.write( "
\n" ); document.write( " \n" ); document.write( "

\n" );