+537 1. For how many integers a does the polynomial x^2 + ax + 10a have integer roots?
2. Find a+b+c if the graph of the equation ax^2+bx+c is a parabola with vertex (5,3), a vertical axis of symmetry, and contains the point (2,0).
3. Find all real numbers a such that the equation x^3 - ax^2 - 2ax + a^2 - 1 = 0 has exactly one real solution in x.
