document.write( "Question 235940: solving systems of equations. solve the system: y=5-3x and 3x+7y=15 \n" ); document.write( "

Algebra.Com's Answer #173804 by checkley77(12844) $\"\"$ $\"About$

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y=5-3x
\n" ); document.write( "3x+7y=15 substitute (5-3x) for y in this equation & solve for x.
\n" ); document.write( "3x+7(5-3x)=15
\n" ); document.write( "3x+35-21x=15
\n" ); document.write( "-18x=15-35
\n" ); document.write( "-18x=-20
\n" ); document.write( "x=-20/-18
\n" ); document.write( "x=10/9 ans.
\n" ); document.write( "y=5-3*10/9
\n" ); document.write( "y=5-30/9
\n" ); document.write( "y=(5*9-30)/9
\n" ); document.write( "y=(45-30)/9
\n" ); document.write( "y=15/9 ans.
\n" ); document.write( "Proof
\n" ); document.write( "3*10/9+7*15/9=15
\n" ); document.write( "30/9+105/9=15
\n" ); document.write( "135/9=15
\n" ); document.write( "15=15 \n" ); document.write( "

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