ANSWER
[tex](g \circ \: f)(0) = - 216[/tex]
EXPLANATION
The functions are:
[tex]f(x) = 2x - 6[/tex]
[tex]g(x) = {x}^{3} [/tex]
[tex](g \circ \: f)(x) =g(f(x))[/tex]
[tex](g \circ \: f)(x) =g(2x - 6)[/tex]
We substitute f(x) into g(x) to obtain:
[tex](g \circ \: f)(x) =(2x - 6)^{3} [/tex]
We now substitute x=0 to obtain;
[tex](g \circ \: f)(0) =(2(0) - 6)^{3} [/tex]
[tex](g \circ \: f)(0) =(- 6)^{3} [/tex]
This simplifies to:
[tex](g \circ \: f)(0) = - 216[/tex]