document.write( "Question 94206: Factor Completely 12x^3-3xy^2 \n" ); document.write( "
Algebra.Com's Answer #68634 by bucky(2189)![]() ![]() ![]() You can put this solution on YOUR website! Given: \n" ); document.write( ". \n" ); document.write( "12x^3 - 3xy^2 \n" ); document.write( ". \n" ); document.write( "First you can look for common factors in the two terms. Notice 3 is a common factor because \n" ); document.write( "it is a factor of 3 in the second term and a factor of 12 in the first term. The same can \n" ); document.write( "be said of x. It is a factor of x in the second term and a factor of x^3 in the first term. \n" ); document.write( ". \n" ); document.write( "So let's factor out 3x from both terms to get: \n" ); document.write( ". \n" ); document.write( "3x(4x^2 - y^2) \n" ); document.write( ". \n" ); document.write( "Now notice that the expression in the parentheses is the difference of two squares. That \n" ); document.write( "is, it can be written as [(2x)^2 - (y)^2]. \n" ); document.write( ". \n" ); document.write( "This makes it fall under the factoring rule for the difference of two squares. This rule \n" ); document.write( "says that: \n" ); document.write( ". \n" ); document.write( "(A^2 - B^2) = (A - B)(A + B) \n" ); document.write( ". \n" ); document.write( "(You can multiply out the right side of this rule and it will help you to see why this \n" ); document.write( "rule is true.) \n" ); document.write( ". \n" ); document.write( "Comparing the left side of the rule to the terms you have in the brackets you can see \n" ); document.write( "that A = 2x and B = y. So you can substitute 2x for every A on the right side of the rule \n" ); document.write( "and y for every B. When you do that you get that [(2x)^2 - (y)^2] factors into (2x - y)(2x +y) \n" ); document.write( ". \n" ); document.write( "Putting this result together with the 3x we factored out earlier makes the factored \n" ); document.write( "result: \n" ); document.write( ". \n" ); document.write( "3x(2x - y)(2x + y) \n" ); document.write( ". \n" ); document.write( "and that's the answer to your problem. \n" ); document.write( ". \n" ); document.write( "Hope this helps you to see a way to go about factoring this problem and to get you familiar \n" ); document.write( "with the factoring rule for the difference between two squares. \n" ); document.write( " \n" ); document.write( " |