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Question 1183143:  The book value of a machine is expressed by the equation V = 60,000  -  7,500 t 
Where V equals the book value in dollars and t equals the age of the machine expressed in years. 
(a) Identify the t and V intercepts. 
(b) Interpret the meaning of the intercepts. 
(c) Interpret the meaning of the slope. 
(d) Sketch the function. 
 Answer by Theo(13342)      (Show Source): 
You can  put this solution on YOUR website! v = 60,000 - 7500 * t 
v = the book value. 
t = the age of the machine in years.
 
 
to find the t-intercept, set v = 0 and solve for t. 
you will get: 
0 = 60,000 - 7500 * t 
add 7500 * t to both sides of the equation to get: 
7500 * t = 60,000 
solve for t to get: 
t = 60,000 / 7500 = 8
 
 
to find the v-intercept, set t = 0 and solve for v. 
you will get: 
v = 60,000
 
 
the t-intercept is the value of t when v = 0. 
since v represents the book value of the machine, the t-intercept tells you when the book value of the machine is 0.
 
 
the v-intercept is the value of v when t = 0. 
since t is the age of the machine in years, the v-intercept tells you the value of the machine when it is new.
 
 
to graph the equation, set y equal to v and x equal to t. 
the graph looks like this:
 
 
 
 
 
 
 
 
the format of the equation is y = mx + b 
m is the slope 
b is the y-intercept.
 
 
replace y with v and x with t and the equation becomes: 
v = mt + b 
what you were shown is v = b + mt 
that became v = 60,000 - 7500 * t 
re-order the terms to get: 
v = -7500 * t + 60,000 
that shows that -7500 is the slope and 60,000 is the v-intercept
 
 
for graphing purposes, y takes the place of v and x takes the place of t.
 
 
-7500 is the slope. 
the slope is the change in y divided by the change in x. 
in this equation, the slope is telling you that the book value of the machine is reduced by 7500 each year.
 
 
 
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