document.write( "Question 657727: What is the elimination method for 3x-5y=30 and 5x+7y=4 \n" ); document.write( "

Algebra.Com's Answer #409989 by chriswen(106) $\"\"$ $\"About$

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Okay for elimination we need to eliminate something. I'll choose to eliminate x. I need both x's to be equal. So I'll multiply the first equation by 5 and the second equation by 3.\r
\n" ); document.write( "\n" ); document.write( "3x-5y=30 ... (i)
\n" ); document.write( "15x - 25y = 150 ... (iii)\r
\n" ); document.write( "\n" ); document.write( "5x + 7y = 4 ... (ii)
\n" ); document.write( "15x + 21y = 12 ... (iv)\r
\n" ); document.write( "\n" ); document.write( "Now eliminate. I will subtract equation 4 from equation 3.\r
\n" ); document.write( "\n" ); document.write( "15x - 25y = 150
\n" ); document.write( "-)15x+21y = 12
\n" ); document.write( "________________
\n" ); document.write( "0x -46y = 138
\n" ); document.write( "y = -138/46
\n" ); document.write( "y = 3\r
\n" ); document.write( "\n" ); document.write( "now I will sub y = 3 into equation 1.\r
\n" ); document.write( "\n" ); document.write( "3x - 5(3) = 30
\n" ); document.write( "3x - 15 = 30
\n" ); document.write( "3x = 45
\n" ); document.write( "x = 45/3
\n" ); document.write( "x = 15\r
\n" ); document.write( "\n" ); document.write( "Therefore, x = 15, y = 3. This was solved via elimination method. \n" ); document.write( "

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