Respuesta :

sub -3 for every x
f(-3)=-2(-3)-3
f(-3)=6-3
f(-3)=3
TSO
You basically substitute x with -3 and solve

f(x) = -2x - 3

f(-3) = -2(-3) - 3
f(-3) = 6 - 3
f(-3) = 3

So when x = -3, f(x) = 3

Your final answer is 3.