document.write( "Question 1180170: For what values of k will the graph of y = 9x^2+3kx+k have no x-intercepts? \n" ); document.write( "
Algebra.Com's Answer #809778 by greenestamps(13200)\"\" \"About 
You can put this solution on YOUR website!


\n" ); document.write( "When the discriminant b^2-4ac is negative.

\n" ); document.write( "a=9
\n" ); document.write( "b=3k
\n" ); document.write( "c=k

\n" ); document.write( "\"b%5E2-4ac=%283k%29%5E2-4%289%29%28k%29=9k%5E2-36k\"

\n" ); document.write( "\"9k%5E2-36k%3C0\"
\n" ); document.write( "\"k%5E2-4k%3C0\"
\n" ); document.write( "\"k%28k-4%29%3C0\"

\n" ); document.write( "The graph of k(k-4) is a parabola that opens upward, with zeros at k=0 and k=4. So the value of the expression is negative only between 0 and 4.

\n" ); document.write( "ANSWER: 0 < k < 4

\n" ); document.write( "
\n" ); document.write( "
\n" );