8
x2 + y2 = 16
It is the Cartesian equation of an ellipse.
It's possible
You can tell if an equation is a function if for any x value that you put into the function, you get only one y value. The equation you asked about is the equation of a line. It is a function.
False.
No, that is a equation.
A function.
-4x + 9y = 0 is the equation of a line in the Cartesian plane and the coordinates of any of the infinite number of points on that line will satisfy the equation.
false
y - |x| is an expression, not a function.
a function
Yes.
-6