Simplify:  a)

If the elevation of Lake Superior is 121 feet above sea level and the elevation of the Caspian Sea is 29 feet below sea level, find the difference of the two elevations. 

Consider the number:                 You should have three answers –  labeled a), b), and c). Please consider that I have to be able to understand what you intend for me to count as the answers to this question.   a) What digit is in the the ten thousands column?  b) What digit is in the hundreds column?  c) What digit is in the ones column? 

  Find the mean absolute deviation

  Options for Q23

  If 750 books are to be sold, about how many sales calls may be necessary?

  Find the average forecast error.

Find the mass of the two-dimensional object. A disk of radius 8 with a density function ρ(x)=10x where x is the distance from the point to the origin. Round your answer to two decimal places.

Find the arclength of y=3×2+3 on 0≤x≤1. Round your answer to three decimal places.

The doubly charged ion N2+ is formed by removing two electrons from a nitrogen atom. What is its ground-state electron? [Ans1] Estimate the energy (in eV) of the least strongly bound level in its L shell? [Ans2]