document.write( "Question 1050486: Find the range of values of p for which 4x^2+12x+15=p(4x+5) has real roots. \n" ); document.write( "
Algebra.Com's Answer #666035 by Fombitz(32388)\"\" \"About 
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Use the discriminant,
\n" ); document.write( "\"4x%5E2%2B12x%2B15=4px%2B5p\"
\n" ); document.write( "\"4x%5E2%2B12x-4px%2B15-5p=0\"
\n" ); document.write( "\"4x%5E2%2B%2812-4p%29x%2B%2815-5p%29=0\"
\n" ); document.write( "So then,
\n" ); document.write( "\"D=b%5E2-4ac\"
\n" ); document.write( "\"D=%2812-4p%29%5E2-4%2815-5p%29%284%29\"
\n" ); document.write( "For real roots,
\n" ); document.write( "\"D%3E=0\"
\n" ); document.write( "\"+%2812-4p%29%5E2-16%2815-5p%29%3E=0+\"
\n" ); document.write( "\"%28144-96p%2B16p%5E2%29-240%2B80p%3E=0\"
\n" ); document.write( "\"16p%5E2-16p-96%3E0\"
\n" ); document.write( "\"p%5E2-p-6%3E=0\"
\n" ); document.write( "\"%28p-3%29%28p%2B2%29%3E=0\"
\n" ); document.write( "Use the critical points, \"p=3\" and \"p=-2\",
\n" ); document.write( "Break up the number line into 3 regions,
\n" ); document.write( "Region 1 : \"p%3C-2\"
\n" ); document.write( "Region 2 : \"-2%3Cp%3C3\"
\n" ); document.write( "Region 3 : \"p%3E3\"
\n" ); document.write( "Choose a value in each region and check the inequality,
\n" ); document.write( "Region 1 : \"p=-3\"
\n" ); document.write( "\"%28-3-3%29%28-3%2B2%29%3E=0\"
\n" ); document.write( "\"-6%28-1%29%3E=0\"
\n" ); document.write( "\"6%3E=0\"
\n" ); document.write( "True
\n" ); document.write( "Region 2 : \"p=0\"
\n" ); document.write( "\"%280-3%29%280%2B2%29%3E=0\"
\n" ); document.write( "\"-6%3E=0\"
\n" ); document.write( "False
\n" ); document.write( "Region 3 : \"p=4\"
\n" ); document.write( "\"%284-3%29%284%2B2%29%3E=0\"
\n" ); document.write( "\"1%286%29%3E=0\"
\n" ); document.write( "\"6%3E=0\"
\n" ); document.write( "True
\n" ); document.write( "So then,
\n" ); document.write( "\"p%3C=-2\"U\"p%3E=3\"\r
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