Which of these represents a Clairaut equation?
y=xy′+(y′)2y = xy' + (y')^2y=xy′+(y′)2
y′+xy=x2y' + xy = x^2y′+xy=x2
y′=y2+x2y' = y^2 + x^2y′=y2+x2
y′′+y=0y'' + y = 0y′′+y=0