Atruck costing 25,000 with a residual value of 5,000 and a 10 year estimated life, what is the book value at 2 years

$25,000 - 5,000 = $20,000
Since the useful life is 10 years or 10% per year, double-declining rate would be 20%

Year 1
$20,000 x .2 = $4000
Book Value = $16,000

Year 2
$16,000 x .2 = $3,200
Book Value = ($16,000-3,200) = $12,800

Where m is the slope of the line and b is the y-intercept of the line, or the y-coordinate of the point at which the line crosses the y-axis. to write an equation in slope-intercept form, given a graph of that equation, pick two points on the line and use them to find the slope. this is the value of m in the equation.