F(×)= mx, then f(a +b) = f(a)+f(b) for all a an b

Question

1 True 2 false 3not enough information  or 4 none need steps please 

Answer 1

f(x) = mx

 

f(a) = ma

f(b) = mb

f(a) + f(b) = ma + mb

 

f(a+b) = m(a+b)

f(a+b) = ma + mb

 

Is f(a)+f(b) = f(a+b)?