Respuesta :

Answer:

12

Step-by-step explanation:

f(x)=x+3

g(x)=x^2-x

[f(x)+g(x)]=[x+3]+[x^2-x]

[f(x)+g(x)]=x+3+(x^2)-x  

x and -x will be cancelled; hence

[f(x)+g(x)]=x^2+3

f(x)+g(x)=(f+g)(X)

(f+g)(x)=x^2+3

(f+g)(-3)=(-3^2)+3

(f+g)(-3)=9+3

(f+g)(-3)=12