Answer:
Part A)
![V(t)=-5,750t+101,250](https://img.qammunity.org/2021/formulas/mathematics/middle-school/ljlurs47n454y6v9e1v3ore94ndcisqr7b.png)
Part B)
![\$55,250](https://img.qammunity.org/2021/formulas/mathematics/middle-school/ttquh41d9j44553xn3yarcjqkyzkbhpe8n.png)
Explanation:
Part A) Express the value of the bulldozer, V, as a function of how many years old it is, t.
Let
V ----> the value of the bulldozer (dependent variable or output value)
t ----> the number of years (independent variable or input value)
we know that
The linear function in slope intercept form is equal to
![V(t)=mt+b](https://img.qammunity.org/2021/formulas/mathematics/middle-school/k5q5tx2mrm4xin7vhe1wp7zuuqu9a5rbif.png)
we have the ordered pairs
(0,101,250) and (15,15,000)
Find the slope
The formula to calculate the slope between two points is equal to
![m=(y2-y1)/(x2-x1)](https://img.qammunity.org/2021/formulas/mathematics/high-school/s22vchztbo0z3zfbr5dy5rbx0ndd5ffwx5.png)
substitute
![m=(15,000-101,250)/(15-0)](https://img.qammunity.org/2021/formulas/mathematics/middle-school/2gnev82eq5cr30wahjzsbfm5d2smkakin1.png)
----> is negative because is a decreasing function
The value of b is the initial value
so
![b=\$101,250](https://img.qammunity.org/2021/formulas/mathematics/middle-school/bpom1bsn6zn2m3rafj6p2rb17y73ofkyvr.png)
substitute
![V(t)=-5,750t+101,250](https://img.qammunity.org/2021/formulas/mathematics/middle-school/ljlurs47n454y6v9e1v3ore94ndcisqr7b.png)
Part B) The value of the bulldozer after 8 years is
For t=8 years
substitute the value of t in the linear equation
![V(t)=-5,750(8)+101,250=\$55,250](https://img.qammunity.org/2021/formulas/mathematics/middle-school/kc6rrj11n02pywqk194yv9x19avfdas50h.png)