document.write( "Question 521313: How would I solve y = 15 - 3x and 7y + 3x = 15 using the substitution method? I tried plugging the y = 15 - 3x for the y but I came up with a decimal answer and I don't think it's supposed to be a decimal? \n" ); document.write( "
Algebra.Com's Answer #346420 by mananth(16946)\"\" \"About 
You can put this solution on YOUR website!
3 x + 1 y = 15 .............1
\n" ); document.write( "7 y = 15 -3 x ---------2
\n" ); document.write( "/ 7 =
\n" ); document.write( " y = 2.14 -0.43 x
\n" ); document.write( "Substitute y in (1)
\n" ); document.write( "3 x + 1 ( 2.14 -0.43 x ) = 15
\n" ); document.write( "3 x + 2.14 + -0.43 x = 15
\n" ); document.write( "3 x -0.43 x = 15 -2.14
\n" ); document.write( "2.57 x = 12.86
\n" ); document.write( "/ 2.57
\n" ); document.write( "x= 5
\n" ); document.write( "Plug the value of x in (1)
\n" ); document.write( "3 x + 1 y = 15
\n" ); document.write( "3 * 5 + 1 y = 15
\n" ); document.write( "15 + 1 y = 15
\n" ); document.write( "1 y = 0
\n" ); document.write( "/ 1
\n" ); document.write( "y= 0
\n" ); document.write( "m.ananth@hotmail.ca
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