If f(a)=a^2, what is the value of (f(a+b)−f(a))/a ?  Choose the correct choice from the following answers:
A) a B) b C) 2b+b^2 D) 2a + b E) 2b - a
start with f(a+b) before start calculations: f(a+b)=(a+b)^2= a^2+2ab+b^2   a^2+2ab+b^2 - a^2/a = (simplify a^2)   2ab+b^2/b = (cancel b's)   = 2b+b^2   Ans : 2b+b^2
<result>C</result>
If f(a)=a^2, what is the value of (f(a+b)−f(a))/a ?