My math teacher hates me :( but idc

Abcd is a parallelogram find the valuse of x

Estimate the area under the curve f(x) = 16 - x^2 from x = 0 to x = 3 by using three inscribed (under the curve) rectangles. answer to the nearest integer.

If f(x) and g(x) are inverse functions of each other, which of the following shows the graph of f(g(x)