Need help on number 3 please!!

Answer:
f(x) - g(x) = x - 3
Step-by-step explanation:
f(x) - g(x) starting with the basic equation
2x - (x + 3) implementing the values into equation
x - 3 subtracting x and 3 from 2x making 2x into 1x (or just x) and making a negative 3