Last question on post test need answer asap

What situation is an example of an observational study

Simply 8x squared + 5(7x squared- x) - 2x =

Find the volume of the solid whose base is the region bounded by f(x), g(x) and the x-axis on the interval [0, 1], and whose cross-sections perpendicular to the y-axis are squares. your work must show the integral, but you may use your calculator to evaluate it. give 3 decimal places for your answe