Function problems

[Jae-LynH534]

Hi. Would someone kindly explain the following problem?

Q. For which of the following is f(a+b) = f(a) +f(b), for all positive numbers a and b?

a. f(x) = x^2
b. f(x) = x+1
C. f(x) = sq rt(x)
d. f(x) = 2/x
e. f(x) = -3x (ANSWER)

[RonPurewal]

• this is the wrong folder for this item (which is from the GMAT Prep software).

• please search the forum before posting. thank you.

https://www.manhattanprep.com/gmat/foru ... t2795.html