Question 164430
Remember GoF is shorthand notation for g(f(x))



{{{g(x)=-x^2-2x+3}}} Start with the given function



{{{g(f(x))=-(2x+3)^2-2(2x+3)+3}}} Plug in {{{f(x)=2x+3}}}



{{{g(f(x))=-(4x^2+12x+9)-2(2x+3)+3}}} FOIL



{{{g(f(x))=-4x^2-12x-9-4x-6+3}}} Distribute



{{{g(f(x))=-4x^2-16x-12}}} Combine like terms.



So GoF is {{{g(f(x))=-4x^2-16x-12}}}