For what values of k does kx2+12x+9=0 have imaginary roots?A detailed (step by step) answer would be great!

Expert Answers

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The function will have imaginary roots when the determinant is negative.  The determinant = (b(squared)-4ac

so: 12(squared) - 4(k)(9)<0

144-36k<0

-36k<-144

k>4

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