Which of the following expressions represents a function?
x = 1
{(3, 2), (3, –2), (4, 5), (4, –5)}
y = 4x − 1
4x2 + y2 = 16

y = 4x − 1

Step-by-step explanation:

∵ A relation is called function if each input value has a different or unique output value,

In the line x = 1,

There are infinite output values for the input value of 1,

So, x = 1 is not a function,

In the relation {(3, 2), (3, –2), (4, 5), (4, –5)},

3 has two output values 2 and - 2,

Thus, {(3, 2), (3, –2), (4, 5), (4, –5)} is not a function,

In line y = 4x - 1,

For each value of x there is a different value of y,

So, y = 4x - 1 is a function,

In the circle, ,

For 2 values of x there is one value of y,

eg : for x = 2 and x = -2,

y = 0,

So, is not a function.

im not sure

step-by-step explanation: