The question isn't specific, and the expression doesn't factorise in an obvious way. The highest degree of the expression is 3 (x3) and the lowest degree is 2 (y2 and xy terms). The graph of x3-56xy+5y2=a is interesting. When a=0, the graph is continuous and contains a closed loop, and passes through the origin. When a<0 the graph is not continuous and splits into a closed elongated oval shape and a line which kinks as it approaches the closed shape near the origin. When a>0 the graph is continuous but doesn't pass through the origin. The loop has a "neck" near the origin so is no longer closed.