a) x^2-y^2=15 b) x^2+y^2=15 c) x+y=15 d) xy=15
It only satisfies a) x^2 - y^2 = 15 Just to make sure ... 2x - 2y dy/dx = 0 dy/dx = 2x/2y = x/y Yup, it is a)
You can ask a new question or answer this question.