Question

Find two years during which the price of the stock was $15

Answer 1

given the expression

`15=0.5t^2-5.6t+25.2`

where

P= price

t=time

t(0)= year 2000

given the formula

`x=-b(\pm√(b^2-4ac))/(2a)`

where

a=5

b=-56

c=102

then

`t=56(\pm√((56)^2-4(5)(102)))/(2(5))`
`t=56(\pm2√(274))/(2*5)`
`t=(28\pm√(274))/(5)`
`t1=(28+√(274))/(5)=8.91`
`t2=(28-√(274))/(5)=2.289`

since t(0)=2000 years

then a time of

t1=8.91 represent the year 2008

t2= 2.28 represent the year 2002