Question 1197810
17.

{{{f(x) = 15x^3 + 13x^2 - 15x + 15}}}
{{{g(x) = 15x + 11}}}



find {{{g(f(9))}}}


first  find {{{g(f(x))}}}

{{{g(f(x))=g(15x^3 + 13x^2 - 15x + 15)}}}

{{{g(f(x))=15(15x^3 + 13x^2 - 15x + 15)+11}}}

{{{g(f(x))=225 x^3 + 195 x^2 - 225 x + 236}}}



then

{{{g(f(9))=225 *9^3 + 195*9^2 - 225*9 + 236}}}

{{{g(f(9))=178031}}}


answer: E.{{{ 178031}}}



18. 

{{{f(x) = -13x^2 - 13x + 14}}}
{{{g(x) = -13x - 11}}}

find {{{g(g(3))}}}

{{{g(g(x))=g( -13x - 11)}}}
{{{g(g(x))=-13( -13x - 11)-11}}}
{{{g(g(x))=169 x + 132}}}

then

{{{g(g(3))=169 *3 + 132}}}
{{{g(g(3))=639}}}

answer:  
A. {{{639}}}