Question 253836
{{{b^2-4ac}}} is the discriminant.
{{{b^2-4ac > 0)}}} 2 real solutions
{{{b^2-4ac = 0)}}} 1 real solution
{{{b^2-4ac < 0)}}} no real solutions

So in the case of {{{-4j^2+3j-28=0}}} the discriminant is {{{9-(4*-4*-28)}}} which is {{{9-(448)= -439}}} so no real solutions.

The graph of {{{-4j^2+3j-28=0}}} demonstrates this {{{ graph( 300, 200, -50, 50, -1000, 50, -4x^2+3x-28) }}}