document.write( "Question 501819: x^-6 - 11x^-3 + 24 = 0\r
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document.write( "I'm confused as to where to start!\r
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document.write( "Thanks,
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document.write( "Tracy \n" );
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Algebra.Com's Answer #338689 by nerdybill(7384) You can put this solution on YOUR website! x^-6 - 11x^-3 + 24 = 0 \n" ); document.write( ". \n" ); document.write( "Let y = x^-3 \n" ); document.write( "then \n" ); document.write( "y^2 = x^-6 \n" ); document.write( ". \n" ); document.write( "So, instead of: \n" ); document.write( "x^-6 - 11x^-3 + 24 = 0 \n" ); document.write( "we can write: \n" ); document.write( "y^2 - 11y + 24 = 0 \n" ); document.write( "now, we can factor the left: \n" ); document.write( "(y-3)(y-8) = 0 \n" ); document.write( "y = {3, 8} \n" ); document.write( "But, we're looking for 'x' NOT 'y', so substitute back into: \n" ); document.write( "y = x^-3 \n" ); document.write( "3 = x^-3 \n" ); document.write( "3 = 1/x^3 \n" ); document.write( "3x^3 = 1 \n" ); document.write( "x^3 = 1/3 \n" ); document.write( "x = cuberoot(1/3) \n" ); document.write( "or, rationalizing \n" ); document.write( "x = cuberoot(3)/3 \n" ); document.write( "and, similarly \n" ); document.write( "x = cuberoot(8)/8 = 2/8 = 1/4\r \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |