To determine which equation represents a parabola, let's analyze each option:
Option A: (x − y)³ = 3
This equation is a cubic equation, not a parabola.
Option B: x/y − y/x = 0
This can be rearranged to form a relationship between x and y, but it does not represent a parabola.
Option C: x/y + 4/x = 0
This equation can be manipulated, but it does not yield a parabolic form.
Option D: (x + y)² + 3 = 0
This equation cannot be satisfied for real numbers since the left side is always positive. It does not represent a parabola either.
Final Analysis
None of the provided options represent a parabola. A standard parabolic equation typically takes the form of y = ax² + bx + c or x = ay² + by + c.