document.write( "Question 245385: Help please.\r
\n" ); document.write( "\n" ); document.write( "1. Solve using the substitution method. Show your work. If the system has no solution or an infinite number of solutions, state this.\r
\n" ); document.write( "\n" ); document.write( "x + 7y = -2
\n" ); document.write( "3x + y = 34
\n" ); document.write( "
\n" ); document.write( "2. Solve using the elimination method. Show your work. If the system has no solution or an infinite number of solutions, state this.\r
\n" ); document.write( "\n" ); document.write( "-4x + 9y = 20
\n" ); document.write( "-2x - 2y = 10 \r
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "

Algebra.Com's Answer #179258 by Fombitz(32388) $\"\"$ $\"About$

You can put this solution on YOUR website!
1. $\"x+%2B+7y+=+-2\"$
\n" ); document.write( "2. $\"3x+%2B+y+=+34\"$ \r
\n" ); document.write( "\n" ); document.write( "From 2,
\n" ); document.write( " $\"3x%2By=34\"$
\n" ); document.write( " $\"y=34-3x\"$
\n" ); document.write( "Substitute into eq. 1,
\n" ); document.write( " $\"x%2B7%2834-3x%29=-2\"$
\n" ); document.write( " $\"x%2B238-21x=-2\"$
\n" ); document.write( " $\"-20x=-240\"$
\n" ); document.write( " $\"x=12\"$
\n" ); document.write( "From eq. 1,
\n" ); document.write( " $\"x%2B7y=-2\"$
\n" ); document.write( " $\"12%2B7y=-2\"$
\n" ); document.write( " $\"7y=-14\"$
\n" ); document.write( " $\"y=-2\"$
\n" ); document.write( "(12,-2)
\n" ); document.write( ".
\n" ); document.write( ".
\n" ); document.write( ".
\n" ); document.write( " $\"-4x+%2B+9y+=+20\"$
\n" ); document.write( " $\"-2x+-+2y+=+10+\"$
\n" ); document.write( "Multiply eq. 2 by -2 and add to eq. 1
\n" ); document.write( " $\"-4x%2B9y%2B4x%2B4y=20-20\"$
\n" ); document.write( " $\"13y=0\"$
\n" ); document.write( " $\"y=0\"$
\n" ); document.write( "From eq. 2,
\n" ); document.write( " $\"-2x-2y=10\"$
\n" ); document.write( " $\"-2x=10\"$
\n" ); document.write( " $\"x=-5\"$
\n" ); document.write( "(-5,0) \n" ); document.write( "

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