Determine which functions are one-to-one.

A) I only
B) I, II
C) I, II, III
D) II only
E) III only

Question

Determine which functions are one-to-one.

A) I only 
B) I, II 
C) I, II, III 
D) II only 
E) III only

Quizplus · Accepted Answer

A function is one-to-one if each element in the domain is paired with exactly one element in the range. 
I) f(x) = x^3 is not one-to-one because, for example, f(2) = f(-2).
II) g(x) = 2x + 3 is one-to-one because any two distinct inputs give distinct outputs. 
III) h(x) = |x| is not one-to-one because, for example, h(2) = h(-2). 
Therefore, the only function that is one-to-one is g(x) = 2x + 3, which is choice D.

Determine Which Functions Are One-To-One