document.write( "Question 73618: I sort of know how to factor a perfect square but I can't figur out how to factor a cube. Factor x*3-125. Do I find the square root of a number? \n" ); document.write( "

Algebra.Com's Answer #52651 by joyofmath(189) $\"\"$ $\"About$

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Let's look at the general case, how to factor $\"a%5E3-b%5E3\"$ .\r
\n" ); document.write( "\n" ); document.write( "By the binomial theorem, $\"%28a-b%29%5E3+=+a%5E3-3a%5E2b%2B3ab%5E2-b%5E3\"$ .
\n" ); document.write( "So, $\"a%5E3+-+b%5E3+=+%28a-b%29%5E3+%2B+3a%5E2b+-+3ab%5E2\"$ .
\n" ); document.write( "Or,

.\r
\n" ); document.write( "\n" ); document.write( "So, for the problem at hand we substitute a=x and b=5 and we get\r
\n" ); document.write( "\n" ); document.write( " $\"highlight%28x%5E3+-+5%5E3+=+%28x-5%29%28x%5E2%2B5x%2B25%29%29\"$ . \n" ); document.write( "

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