If g (x)=2x + 1, find g (a + h)- g (a).
2(a+h)+1-(2a+1) = 2a+2h+1-2a-1 = 2h. 2h is your final answer.
2(a+h)+1-(2a+1) = 2a+2h+1-2a-1 = 2h. 2h is the correct answer.