Help me to solve this problem

In pqr the obtuse angle is 105 and the shorter sides measure 4 and 7 units rounded to the nearest tenth what is the area of triangle pqr

What is the answer to this question? i'm a bit stumped. also how do i do it? 5(x - 4) = 2(x + 5)

These tables represent a quadratic function with a vertex at (0, -1). what is the average rate of change for the interval from x = 9 to x = 10?