document.write( "Question 247645: solve : \"x%5E2%28x%2B8%29%3C0\" \n" ); document.write( "
Algebra.Com's Answer #180589 by RicaMath(8)\"\" \"About 
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Here, we see two numbers are being multiplied together in the inequality (\"x%5E2\" and \"%28x%2B8%29\"). And we know that the only way to multiply two numbers together and get a number less than 0 is to multiply a positive and a negative number together. (positive * positive = positive; and negative * negative = positive)
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\n" ); document.write( "Thus, we know that \"x%5E2%28x%2B8%29%3C0\" is true in either of the following situations:
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\n" ); document.write( "1. \"x%5E2+%3C+0\" and \"%28x%2B8%29+%3E+0\"
\n" ); document.write( "2. \"x%5E2+%3E+0\" and \"%28x%2B8%29+%3E+0\"
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\n" ); document.write( "If you look at the first statement carefully, you may note that it can never be true. As previously stated, positive * positive = positive; and negative * negative = positive, so there is no way you can take any integer, square it, and get a negative number. This means, we only need to concern ourselves with the second situation, \"x%5E2+%3E+0\" and \"%28x%2B8%29+%3E+0\".\r
\n" ); document.write( "\n" ); document.write( "So, let's solve the two inequalities:
\n" ); document.write( "\"x%5E2+%3E+0\"
\n" ); document.write( "\"x+%3E+0\" (get the square root of both sides)
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\n" ); document.write( " \"%28x%2B8%29+%3E+0\"
\n" ); document.write( "\"x+%3E+-8\"
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\n" ); document.write( "So, we get \"x+%3E+-8\" as our answer. (because all items > -8 are also > 0, so we use the more restrictive option as our final answer to ensure all possibilities work.)
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\n" ); document.write( "We can always double check our work. Let's take \"x+=+-10\", as that satisfies our answer condition. Plugging it into our original inequality:
\n" ); document.write( "\"%28-10%29%5E2%28-10%2B8%29+%3C++0\"
\n" ); document.write( "\"100%28-2%29+%3C++0\"
\n" ); document.write( "\"-200+%3C++0\", which is a true statement. \n" ); document.write( "

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