document.write( "Question 1177934: Given y = −3x^2 + kx − 12 for k > 0, find the value(s) of k such that y < 0 for all x. \n" ); document.write( "
Algebra.Com's Answer #807096 by MathLover1(20850)\"\" \"About 
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\n" ); document.write( " \"y+=+-3x%5E2+%2B+kx+-12+\"\r
\n" ); document.write( "\n" ); document.write( "for \"k+%3E+0\", find the value(s) of \"k\" such that \"y+%3C+0\" for all \"x\".\r
\n" ); document.write( "\n" ); document.write( " \"y=-3x%5E2+%2B+kx+-12+\"\r
\n" ); document.write( "\n" ); document.write( "in the standard form\r
\n" ); document.write( "\n" ); document.write( "\"y=ax%5E2%2Bbx%2Bc+\"\r
\n" ); document.write( "\n" ); document.write( "\"a=-3\", \"b=k\", \"c=-12\"\r
\n" ); document.write( "\n" ); document.write( "discriminant: \r
\n" ); document.write( "\n" ); document.write( "\"b%5E2-4ac=k%5E2-4%28-3%29%28-12%29=k%5E2-4%2836%29=k%5E2-144\"\r
\n" ); document.write( "\n" ); document.write( "if \"k%5E2-144=0\"=>\"k=sqrt%28144%29\"=>\"k=12\" or \"k=-12\"\r
\n" ); document.write( "\n" ); document.write( "the value(s) of \"k\" such that \"y+%3C+0\" for all \"x\":\r
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\n" ); document.write( "\n" ); document.write( "and solution is: \"-12%3Ck%3C12+\" \r
\n" ); document.write( "\n" ); document.write( "or set { \"-11\",\"-10\",\"-9\",.........,\"9\",\"10\",\"11\" }
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