document.write( "Question 221974: Solve by the elimination method. 7r-5s=-12 5r-7s=76\r
\n" ); document.write( "\n" ); document.write( "What is the solution of the system? \n" ); document.write( "
Algebra.Com's Answer #166334 by checkley77(12844)\"\" \"About 
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7r-5s=-12 multiply by -5
\n" ); document.write( "5r-7s=76 multiply by 7 & add.
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\n" ); document.write( "-35r+25s=60
\n" ); document.write( "35r-49s=532
\n" ); document.write( "-----------
\n" ); document.write( "-24s=592
\n" ); document.write( "s=592/-24
\n" ); document.write( "s=-74/3 ans.
\n" ); document.write( "7r-5*-74/3=-12
\n" ); document.write( "7r+370/3=-12
\n" ); document.write( "7r=-12-370/3
\n" ); document.write( "7r=(-12*3-370)/3
\n" ); document.write( "7r=(-36+370)/3
\n" ); document.write( "7r=-406/3
\n" ); document.write( "r=(-406/3)/7
\n" ); document.write( "r=-406/21 ans.
\n" ); document.write( "Proof:
\n" ); document.write( "5*-406/21-7*-74/3=76
\n" ); document.write( "-2030/21+518/3=76
\n" ); document.write( "-2030/21+7*518/3*7=76
\n" ); document.write( "-2030/21+3626/21=76
\n" ); document.write( "1596/21=76
\n" ); document.write( "76=76
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