Your company has purchased a $12,000 machine that has a useful life of 8 years. The salvage value of the machine at the end of 8 years is $2,000. (Hint: on the y-axis indicate the value and on the x-axis the years.) (a) Write a linear equation that describes the book value of the machine each year. Hint: From the above information find the slope and the y-intercept. (b)What is the book value of the machine at the end of year 4?