What to do here? i don't really understand what a geometric sequence is very well.

Find the number of positive three-digit even integers whose digits are among 9, 8, 7,5, 3, and 1.

Don't know how to find x given these segment lengths

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