Respuesta :

f(x) = 6x + 3,   g(x) = x - 7

(f + g)(3) = f(3) + g(3)

f(x) = 6x + 3

f(3) = 6*3 + 3 = 18 + 3 = 21

g(x) = x - 7

g(3) = 3 - 7 = - 4

(f + g)(3) = f(3) + g(3) = 21 + (-4) = 21 - 4 = 17