Answer: x² + y² = 9 is not a function
Step-by-step explanation: In order for an equation to represent a function any single value of x must have at most one corresponding value of y which satisfies the equation. and therefore the equation is not a function.
x^2+y^2=9
if for example x=0
There are two values for y(namely+3 and -3) which satisfy the equation and therefore the equation is not a function
