Question

S(t) = -105t + 945 to determine the salvage value, S(t), in dollars, of a table saw t years after its purchase. How long will it take the saw to depreciate completely? A. 11 years B. 8 years C. 7 years D. 9 years

Answer 1

`\large \boxed{\sf \bold{D.} \ 9 \ years}`

Explanation:

`S(t) = -105t + 945`

For the value to depreciate completely, the amount has to be equal to 0 dollars.

Set S(t) to 0.

`0 = -105t + 945`

Solve for the time t.

Subtract 945 from both sides.

`0 -945= -105t + 945-945`

`-945=-105t`

Divide both sides by -105.

`\displaystyle (-945)/(-105)=(-105t)/(-105)`

`9=t`

It will take 9 years for the saw to depreciate completely.

Answer 2

D

Explanation:

When something depreciates completely, it will have a total value of 0 dollars. Therefore, set the equation to zero and solve for t to find the years.

`S(t)=-105t+945\\0=-105t+945\\-105t=-945\\t=9`

Therefore, the table saw will completely depreciate after 9 years.