A computer purchased for $1,150 loses 20% of its value every year.

The computer's value can be modeled by the functionv(t)-ab^t, where v is the dollar value andt

the number of years since purchase.

(a)In the exponential model a=_____________ b=________________

(b)In how many years will the computer be worth half its original value? round answer to 1 decimal place.

the answer is ____________years