For which of the following does f(p)−f(q)=f(p−q) for all values of p and q? Choices:	A) f(a)=a^2	B) f(a)=a/2	C) f(a)=a+5	D) f(a)=2a−1	E) f(a)=|a|
To solve this easiest way is just put the value and see that if it equals or not.   with option 1. f(p) = p^2 and f(q) = q^2   so L.H.S = p^2 - q^2   and R.H.S = (p-q)^2 ==&gt; p^2 + q^2 -2pq.   so L.H.S not equal to R.H.S   with option 2. f(p) = p/2 and f(q) = q/2   L.H.S = p/2 - q/2 ==&gt; 1/2(p-q)   R.H.S = (p-q)/2   so L.H.S = R.H.S which is the correct answer.   f(a)=a/2
<result>B</result>
For which of the following does f(p)−f(q)=f(p−q) for all values of p and q?