Answer: The relation x^2 + y^2 = 25 does not represent y as a function of x. This is because for a given value of x, there are multiple values of y that would satisfy the equation. For example, for x = 3, y = 4 and y = -4 both satisfy the equation. In a function, each value of the independent variable (in this case, x) must correspond to only one value of the dependent variable (in this case, y).
It's an equation of a circle with a center (0,0) and a radius of 5.
Explanation: