Use arithmetic series formula to calculate: 15+10+5+0+(-5)+(-10)+(-15)+...+(-5m)

A company buys a machine for $175,000. During the next 5 years, the machine will depreciate at a rate of 30% per year. (That is, at the end of each year, the depreciated value will be 70% of what it was at the beginning of the year.) (a) Write an expression for the value of the machine after n years. (b) Compute the depreciated values of the machine for the first 5 years.

Find the sum: -9+ – 10 + – 11 + ... + – 15 -

Find the common difference of the arithmetic sequence: {- 7, - 11, 15, 19, 23, ...} d 3D