Answer:
[tex]f(g(x)) = -126x^{6} +75x^{4} -15x^{2} +1[/tex]
Step-by-step explanation:
[tex]f(x) = x^{3} \\g(x) = -5x^{2}+1\\f(g(x)) = f(-5x^{2}+1)\\f(g(x)) = (-5x^{2}+1)^{3\\\\[/tex]