ANSWER
0
EXPLANATION
The given expression is:
[tex] \sqrt{ {b}^{2} - 4ac} [/tex]
We want to find the value of this expression when, a=1, b=-6 and c=9.
We substitute the given values into the expression to obtain:
[tex] \sqrt{ { (- 6)}^{2} - 4(1)(9)} [/tex]
We evaluate to obtain:
[tex] \sqrt{ 36- 36} [/tex]
This simplifies to
[tex] \sqrt{ 0} = 0[/tex]
The correct answer is the 3rd option.
