Function Representation and Graph Analysis

Which of the following graphs represents a function?

• A graph of y=x

• A graph of x=y^2

• A graph of x^2+y^2=9

• A graph of x=4

Which of the following equations does NOT represent a function?

• y = x^2

• y = 3

• x = y^2

• y = |x|

A graph of the equation x^2 + y^2 = 9 is shown. Does this graph represent a function?

• Yes, because a vertical line intersects the graph at only one point.

• No, because a vertical line intersects the graph at more than one point.

• Yes, because it is a closed curve.

• No, because it is symmetrical about the x-axis.

Consider the equations y = 3 and x = 4. Which statement correctly describes whether they represent functions?

• Both y = 3 and x = 4 represent functions.

• Neither y = 3 nor x = 4 represents a function.

• y = 3 represents a function, but x = 4 does not.

• x = 4 represents a function, but y = 3 does not.