
David M. answered 11/07/20
Learning through understanding
A.
One important piece of information is that the bulldozer depreciation is "linear". This means a "straight line" if graphed (the "line" in "linear"). This means the depreciation can be represented by one of the 3 forms of linear equations:
y=mx+b, slope intercept
y-y=m(x-x), point slope, rewritten as y=m(x-x)+y to set up to convert to function notation.
Ax+By=C, standard form, rewritten as y=(C-Ax)/B to set up to convert to function notation.
m signifies the slope, which is the same as the rate of change, or the change in y divided by the change in x. In our problem, V is expressed as a function of t, so –
m=($124950–$11900)/(0years–19years)= –$5950
Keeping in mind the the changes have to be calculated in the same direction, i.e.
the result of starting value minus end value divided by the result of the start time minus the end time OR
the result of end value minus start value divided by the result of the end time minus the start time.
In the slope intercept form of linear equation, b is the y intercept, or the value of y when x is zero.
We are given that when time starts (upon purchase), t=0, the value of the bulldozer, V, is $124950.
So, by using y=mx+b, we have
V(t)= –($5950years)t+$124950
B.
V(6)= –($5950years)(6)+.$124950
You can make the final calculation.