If f of x is equal to 6 x cubed plus 5 x , g of x is equal to 3 x squared plus 5 , and h of x is equal to 9 x squared minus 8 , what is the degree of f of g of h of x ?

The degree of a composition is found by multiplying the degrees of the polynomials. Here, f has degree 3, g has degree 2, and h has degree 2, so the degree of f(g(h(x))) is 3 × 2 × 2 = 12. Therefore, the correct choice is 12.

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