"f(x) is O(g(x))" to show that x4 + 9x3 +4x + 7 is 0(x4)

Determine whether the points (–3,–6) and (2,–8) are in the solution set of the system of inequalities below. x ? –3 y < 5? 3x + 2 a. the point (–3,–6) is not in the solution set, and the point (2,–8) is in the solution set. b. neither of the points is in the solution set. c. the point (–3,–6) is in the solution set, and the point (2,–8) is not in the solution set. d. both points are in the solution set.

The center of the circumscribed circle lies on line segment and the longest side of the triangle is equal to the of the circle.

How to do this , and can some one explain