The midpoint of the interval whose boundaries are 27.5 and 38.5 is

33

Step-by-step explanation:

Sounds as tho' you're working with a number line.  On this line you have 27.5 and 38.5 marked, and your task is to determine the midpoint.  To do this, find the average of 27.5 and 38.5:

27.5 + 38.5      66

= 33.  The desired midpoint is 33.

        2                2

the graph in the attached figure

step-by-step explanation:

we have

using a graphing tool

the graph in the attached figure

the roots are ( x-intercepts) x=-0.5,x=1,x=3

the y-intercept is the point (0,3)