document.write( "Question 409413: In solving the equation (x + 2)(x – 2) = 32, Eric stated that the solution would be
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document.write( "x + 2 = 32 => x = 30
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document.write( "or
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document.write( "(x – 2) = 32 => x = 34
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document.write( "However, at least one of these solutions fails to work when substituted back into the original equation. Why is that? Please help Eric to understand better; solve the problem yourself, and explain your reasoning. \n" );
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Algebra.Com's Answer #288232 by jsmallt9(3758)![]() ![]() ![]() You can put this solution on YOUR website! There is no special product rule for 32. There are an infinite number of products that can equal 32. \n" ); document.write( "But there is a special product rule for 0. If a product is zero, then one (or more) of the factors must be zero. So we need to manipulate the equation so it is a product that equals zero. \n" ); document.write( "First we simplify the left side: \n" ); document.write( " \n" ); document.write( "Next we make one side zero. Subtracting 32 from each side we get: \n" ); document.write( " \n" ); document.write( "Now we factor. This is a difference of squares so it is easy to factor: \n" ); document.write( "(x+6)(x-6) = 0 \n" ); document.write( "With this product that equals zero we know that one of the factors must be zero. So: \n" ); document.write( "x+6 = 0 or x-6 = 0 \n" ); document.write( "Solving each of these we get: \n" ); document.write( "x = -6 or x = 6 \n" ); document.write( "So there are two solutions to the original equation. \n" ); document.write( " |