Question

In which choice is y a function of x?А(1, 3), (3, 4), (4, 5), (5, 6)B.(2, 0), (2, 3), (4, 5), (6, 7)C.(2, 5), (4, 8), (6, 10), (2, 12)

Answer 1

To determine if y is a function of x, there must be a unique values of y for every unique values of x or vice versa

For example :

(1, 2) (1, 3) : this y is NOT a function of x because the values of x is not unique.

(1, 2) (3, 4) : this y is a function of x because there is a unique values for x and y

From the given problem :

Let's check Option A :

As you can see, there are unique values of x {1, 3, 4, 5} and unique values of y {3, 4, 5, 6}

Therefore this y is a function of x

Let's check Option B :

As you notice, there are 2 same values of x with different values of y (2, 0) and (2, 3)

Therefore, y is NOT a function of x

Let's check Option C :

There are also same values of x, (2, 5) and (2, 12)

Therefore, y is NOT a function of x

Let's check Option D :

Still, there are same values of x, (6, 2) and (6, 8)

Therefore, y is NOT a function of x

The correct answer is OPTION A

Just remember that for every value of x there must be a different value of