document.write( "Question 796163: The domain of the function log 3 (5 + 4x −x 2) is \n" ); document.write( "
Algebra.Com's Answer #481259 by fcabanski(1391)\"\" \"About 
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The domain of a log function is all values greater than zero. The log of a negative number is not real.


\n" ); document.write( "In this case, that means \"5+%2B+4x+-x%5E2+%3E=+0\" or \"x%5E2+-4x+-+5+%3C=+0\"


\n" ); document.write( "(x-5)(x+1) < 0


\n" ); document.write( "x = 5 and x = -1


\n" ); document.write( "Because it's an inequality, set up intervals based on these roots, and test the equation in these intervals.


\n" ); document.write( "-infinity to -1, -1 to 5, and 5 to infinity. Since the inequality is greater than or =, the solution range will include the roots. You can plug them into the equation to prove it.

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\n" ); document.write( "\n" ); document.write( "-infinity to -1: Use -10. -10^2 -4(-10) -5 = 135 > 0, so this interval is not part of the solution.


\n" ); document.write( "-1 to 5: Use 0. 0 - 0 -5 = -5 < 0, so this interval is part of the solution.


\n" ); document.write( "5 to infinity: Use 10. 10^2 - 4(10) - 5 = 55 > 0, so this interval is not part of the solution.


\n" ); document.write( "The domain is -1 <= x <= 5 \n" ); document.write( "

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