document.write( "Question 28021: x^-2-64y^-2
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\n" ); document.write( "\n" ); document.write( " 9y-72x\r
\n" ); document.write( "\n" ); document.write( "i'm having trouble with this one. \n" ); document.write( "
Algebra.Com's Answer #15266 by sdmmadam@yahoo.com(530)\"\" \"About 
You can put this solution on YOUR website!
x^-2-64y^-2
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\n" ); document.write( "\n" ); document.write( " 9y-72x\r
\n" ); document.write( "\n" ); document.write( "=[(1/x^2)-(64/y^2)]/(9y-72x) [using a^-m = (1/a^m)]
\n" ); document.write( "=(y^2-64x^2)/[9x^2y^2(y-8x)]
\n" ); document.write( "[finding the lcm in the nr and taking out 9 in the dr]
\n" ); document.write( "=[(y+8x)(y-8x)]/[9x^2y^2(y-8x)]
\n" ); document.write( "[using formula p^2-q^2 = (p+q)(p-q) and here p =y and q = 8x]
\n" ); document.write( "=(y+8x)/9x^2y^2 (cancelling (y-8x)in the nr and in the dr)\r
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