[GmatG]

Originally Posted by Retake_GMAT

f(x) = x^2

f(a + b) = (a+b)^2 which is not equal to a^2 + b^2 i.e. f(a) + f(b)


f(x) = x + 1

f(a + b) = a+b+1 which is not equal to a+1 + b+1 i.e. f(a) + f(b)


f(x) = sqrt x

f(a + b) = sqrt(a+b) which is not equal to sqrt(a) + sqrt(b) i.e. f(a) + f(b)


f(x) = 2/x

f(a + b) = 2/(a+b) which is not equal to 2/a + 2/b i.e. f(a) + f(b)


f(x) = -3 x

f(a + b) = -3(a+b) = -3a -3b = f(a) + f(b)

ans E

IMO E. Same as above.