document.write( "Question 165809: How would you solve the following equation by factoring and applying the Zero-Product Property?\r
\n" ); document.write( "\n" ); document.write( "\"x%5E4-81=0\"
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Algebra.Com's Answer #122219 by MRperkins(300)\"\" \"About 
You can put this solution on YOUR website!
\"x%5E4-81\" is the same thing as saying \"%28x%5E2%29%5E2-9%5E2\" You may be familiar with the special rule for factoring \"the difference of 2 perfect squares\"
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\n" ); document.write( "The difference of two perfect squares is as follows:
\n" ); document.write( "\"a%5E2-b%5E2=%28a-b%29%28a%2Bb%29\"
\n" ); document.write( "this can be proven true by foiling (a-b)(a+b)=\"a%5E2%2Bab-ab-b%5E2\"=\"a%5E2-b%5E2\"
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\n" ); document.write( "So...in this equation
\n" ); document.write( "\"%28x%5E2%29%5E2-9%5E2=0\"
\n" ); document.write( "\"a=x%5E2\" and \"b=9\"
\n" ); document.write( "so (x^2-9)(x^2+9)=0
\n" ); document.write( "the Zero-Product Property says that when 2 numbers are multiplied together, if either number is zero, then the product will be zero.
\n" ); document.write( "so
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\n" ); document.write( "the equation will be true when (x^2-9)=0 or when (x^2+9)=0
\n" ); document.write( "\"x%5E2-9=0\"
\n" ); document.write( "add 9 to each side
\n" ); document.write( "\"x%5E2=9\"
\n" ); document.write( "take the square root of each side
\n" ); document.write( "\"x=%2B-3\"
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\n" ); document.write( "\"x%5E2%2B9=0\"
\n" ); document.write( "Subtract 9 from each side
\n" ); document.write( "\"x%5E2=-9\"
\n" ); document.write( "take the square root of each side
\n" ); document.write( "\"x=SQRT%28-9%29\" since we are unable to take the square root of a negative number, this is not a real solution.
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\n" ); document.write( "so
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\n" ); document.write( "The final answer is \"x=%2B-3\" but the question is asking for all of the above work.
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\n" ); document.write( "Tutoring available
\n" ); document.write( "contact justin.sheppard.tech@hotmail.com for more information
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