A building with a cost of $1,800,000 has an estimated residual value of $125,000, has an estimated useful life of 40 years, and is depreciated by the straight-line method. c. If at the start of the twenty-ninth year it is estimated that the remaining life is 5 years and that the residual value is $80,000, what is the depreciation expense for each of the remaining 5 years?

First locate the turning point (vertex) of the graph. which is at the coordinates x=5 and y=9 or (5; 9).to determine whether it's a maximum or mininum value, you have to discern whether the vertex's y-value is the highest value or lowest value the graph can reach. since the vertex's y-value, 9 is the highest value the graph can reach, it will be a maximum.another basic way to determine whether the vertex's value is max or min is to see if the graph is smiling or sad. if it's smiling, the turning point/vertex would be a minimum, while a sad parabola would have a maximum y-value at the vertex.