1. The problem statement, all variables and given/known data 2) Given a cubic equation y = (x+5)(ax^2 + bx - 2). Give conditions on a and b for the equation to represent the following curve. The curve is attached to the email. http://img35.imageshack.us/img35/8246/question2o.png [Broken] 2. Relevant equations 3. The attempt at a solution I know that a>0. Since there are 3 intersections with the x-axis, then for (ax^2 + bx - 2), b^2 - 4ac > 0. b^2 - 4(a)(-2) > 0 b^2 + 8a > 0 b^2 > -8a If i differentiate it, I get 3ax^2 + 2bx + 10ax + 5b - 2 Since there are 2 stationary points, B^2 - 4ac = (2b + 10a)^2 - 4(3a)(5b-2) > 0 b^2 - 5ab + 25a^2 + 6a > 0 and I'm stucked again. Which approach is correct? Thanks.