document.write( "Question 272377: Solving using the substitution method: \r
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document.write( "8x - 5y = -47
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document.write( "4x + 3y = -7\r
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document.write( "I got some help from the site, but I dont know how it derived to that answer. When doing it long hand, I couldn't get the same results.\r
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document.write( "Expressing x as a function of y (from the first equation) x = (-47 +5y)/8
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document.write( "Substituting this expression into the second equation:\r
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document.write( "4(-47-5y)/8+3y = -7\r
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document.write( "Simplifying this expression:\r
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document.write( "44y = 132 or y = 3\r
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document.write( "Now, substituting y = 3 back into the x expressed as a function of y:
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document.write( "x = (-47+5y)/8 = -4
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Algebra.Com's Answer #199265 by scott8148(6628)![]() ![]() You can put this solution on YOUR website! take advantage of easy ratios of coefficients\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "4x + 3y = -7 ___ 4x = -3y - 7\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "2(4x) - 5y = -47\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "substituting ___ 2(-3y - 7) - 5y = -47\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "-6y - 14 - 5y = -47\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "-11y = -33 ___ y = 3\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "substituting ___ 4x = -3(3) - 7 ___ 4x = -16 ___ x = -4 \n" ); document.write( " |