You both forgot the last part of the question : "such that the resulting number is a specific integer."
Rephrasing a bit
Quote:
Assuming a, b, c and d are known, what is the best method to resolve the remaining variables: x, y in order that the formula yields a specific integer A when
A=2*x^3+(19/260*a60*b*y)*x^2+(21/2+314*a+30*d*y+30*c+314*b*y)*x+2+205*a+11*c+900*b*y*c+420*a*b*y+210*a^2+210*b^2*y^2+11*d*y+900*a*d*y+900*b*y^2*d+205*b*y+900*a*c

Jacob