00:01
Hi, for the given equation bx2 plus cx plus a, it has all the roots are imaginary.
00:06
For all actual actual actual actual real values, this expression has, or the given option, where to choose.
00:11
So this expression is greater than 4a, b or less than 4a, or less than negative 4a, or greater than negative 4ab.
00:18
Let's work on this.
00:22
So here we have roots are imaginary, so we can say that c square negative 4ab is less than 0, or we have c square is less than 4ab, or we have c square is less than 4ab, or we have.
00:32
Negative c squared is greater than negative 480 by we have done this or it will be later on clear to you now the given expression if we have this expression here we have what on this expression we have that is fx let's say we have f dash x uh this is f x here f dash x would be 6 b square plus 6 bc right so uh and if i not f double dash x that is coming out to be 6 b square x here right right 6b square x plus 6bc.
01:07
So it's going to be 6b squared.
01:13
So b squared is poster.
01:14
This is possible to be greater than 0.
01:16
That means it has a minimum value, right? so the minimum value is given as the minimum value is given as that will be f of.
01:25
So we have put f -x equal to 0.
01:28
So we'll have 6 b squared x plus 6 bc is equal to 0...