Answer:
-12
Step-by-step explanation:
we know that
(fºg)(x)=f(g(x))
To find out the composite function f(g(x)) substitute the variable x in the function f(x) by the function g(x)
we have
[tex]f(x)=-3x-9[/tex]
[tex]g(x)=x+7[/tex]
so
[tex]f(g(x))=-3(x+7)-9[/tex]
For x=-6
substitute
[tex]f(g(-6))=-3(-6+7)-9[/tex]
[tex]f(g(-6))=-3(1)-9[/tex]
[tex]f(g(-6))=-12[/tex]
