document.write( "Question 807678: Please solve this of substitution
\n" ); document.write( " 5x-9y=29
\n" ); document.write( " 12x+y=47 \n" ); document.write( "

Algebra.Com's Answer #486484 by KMST(5328) $\"\"$ $\"About$

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To solve a system of linear equations like $\"system%285x-9y=29%2C12x%2By=47%29\"$ by substitution,
\n" ); document.write( "we solve one equation for one variable,
\n" ); document.write( "and substitute the expression found for that variable into the other equation.\r
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\n" ); document.write( "\n" ); document.write( "In the case of $\"system%285x-9y=29%2C12x%2By=47%29\"$ , the easiest start is
\n" ); document.write( "to solve for $\"y\"$ in $\"12x%2By=47\"$ .
\n" ); document.write( " $\"12x%2By=47\"$
\n" ); document.write( " $\"y=47-12x\"$
\n" ); document.write( "Substituting $\"47-12x\"$ for $\"y\"$ in $\"5x-9y=29\"$ we get
\n" ); document.write( " $\"5x-9%2847-12x%29=29\"$
\n" ); document.write( " $\"5x-423%2B108x=29\"$
\n" ); document.write( " $\"5x%2B108x=29%2B423\"$
\n" ); document.write( " $\"113x=452\"$
\n" ); document.write( " $\"x=452%2F113\"$
\n" ); document.write( " $\"highlight%28x=4%29\"$
\n" ); document.write( "Now, we plug that value into $\"y=47-12x\"$ to find $\"y\"$ :
\n" ); document.write( " $\"y=47-12%2A4\"$
\n" ); document.write( " $\"y=47-48\"$
\n" ); document.write( " $\"highlight%28y=-1%29\"$ \n" ); document.write( "

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