Use four subrectangles to approximate the volume of the object whose base is the region and , and whose height is given by . Find an overestimate and an underestimate and average the two.

This is what i found “an explicit formula designates the nth term of the sequence, as an expression of n (where n = the term's location). it defines the sequence as a formula in terms of n. this example is an arithmetic sequence(the same number, 5, is added to each term to get to the next term).” i hope this you for what your looking for. can you plz mark me brainliest?

Basic algebra equation. first set up your equation: divide out 9.and now you are left with 2x + 4 = 8.