For x2+xy+y2=7x^2 + xy + y^2 = 7x2+xy+y2=7, dy/dx=dy/dx =dy/dx=A2x+yx+2y\dfrac{2x + y}{x + 2y}x+2y2x+yB−2x+yx+2y-\dfrac{2x + y}{x + 2y}−x+2y2x+ycheck_circleC−2x2y\dfrac{-2x}{2y}2y−2xD−xy-\dfrac{x}{y}−yxExplanation2x+y+xy′+2yy′=0⇒y′(x+2y)=−(2x+y)⇒y′=−(2x+y)/(x+2y)2x + y + x y' + 2 y y' = 0 \Rightarrow y'(x + 2y) = -(2x + y) \Rightarrow y' = -(2x+y)/(x+2y)2x+y+xy′+2yy′=0⇒y′(x+2y)=−(2x+y)⇒y′=−(2x+y)/(x+2y).