If $$x + y + z = 3, xy + yz + zx = -12$$ and $$xyz = -16$$, then the value of $$\sqrt{x^3 + y^3 + z^3 + 13}$$ is:
$$x+y+z=3$$
$$x+y=3-z$$........(1)
$$\left(x+y\right)^3=\left(3-z\right)^3$$
$$x^3+y^3+3xy\left(x+y\right)=27-z^3-3.3.z\left(3-z\right)$$
$$x^3+y^3+3xy\left(3-z\right)=27-z^3-9z\left(x+y\right)$$Â [From (1)]
$$x^3+y^3+9xy-3xyz=27-z^3-9xz-9yz$$
$$x^3+y^3+z^3=27-9xy-9xz-9yz+3xyz$$
$$x^3+y^3+z^3=27-9\left(xy+yz+zx\right)+3xyz$$
$$x^3+y^3+z^3=27-9\left(-12\right)+3\left(-16\right)$$
$$x^3+y^3+z^3=27+108-48$$
$$x^3+y^3+z^3=87$$.......(2)
$$\sqrt{x^3+y^3+z^3+13}=\sqrt{87+13}$$
$$=\sqrt{100}$$
$$=10$$
Hence, the correct answer is Option C
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