To calculate the cumulative total of payments made toward the principal of a loan, you use the function.

Amachine purchased three years ago for $720,000 has a current book value using straight-line depreciation of $400,000: its operating expenses are $60,000 per year. a replacement machine would cost $480,000, have a useful life of nine years, and would require $26,000 per year in operating expenses. it has an expected salvage value of $130,000 after nine years. the current disposal value of the old machine is $170,000: if it is kept 9 more years, its residual value would be $20,000. calculate the total costs in keeping the old machine and purchase a new machine. should the old machine be replaced?

The green revolution is a scientific breakthrough that improved seeds for basic crops. how did the green revolution impact the supply of basic crops such as wheat and corn? the supply of wheat and corn increased. there was no impact on the supply of basic crops. the supply of basic crops did not change, but the quantity supplied of basic crops increased. the supply of wheat and corn decreased.

Oz makes lion food out of giraffe and gazelle meat. giraffe meat has 18 grams of protein and 36 grams of fat per pound, while gazelle meat has 36 grams of protein and 18 grams of fat per pound. a batch of lion food must contain at least "46,800" grams of protein and 70,200 grams of fat. giraffe meat costs $1/pound and gazelle meat costs $2/pound. how many pounds of each should go into each batch of lion food in order to minimize costs? hint [see example 2.]