ANSWER
B. -3,3,-6
EXPLANATION
We equate the given polynomial to zero.
[tex] {x}^{3} + 6 {x}^{2} - 9x - 54 = 0[/tex]
Factor by grouping;
[tex] {x}^{2} (x + 6) - 9(x + 6) = 0[/tex]
Factor further;
[tex]( {x}^{2} - 9)(x + 6) = 0[/tex]
Either
[tex] {x}^{2} - 9 = 0 \: or \: x + 6 = 0[/tex]
[tex] {x}^{2} = 9 \: or \: x = - 6[/tex]
[tex]x = \pm \sqrt{9} \: or \: x = - 6[/tex]
[tex]x = \pm 3 \: or \: x = - 6[/tex]
The zeroes are
x=3,-3,-6