SOLUTION: I have an quadratic equation that has to do with graphing and its due tomorrow night (4/16/2010). P=7t^2+8000. 8000 represents the population (p0), t is the time meaning years. t=o

Algebra ->  Logarithm Solvers, Trainers and Word Problems -> SOLUTION: I have an quadratic equation that has to do with graphing and its due tomorrow night (4/16/2010). P=7t^2+8000. 8000 represents the population (p0), t is the time meaning years. t=o      Log On


   



Question 292988: I have an quadratic equation that has to do with graphing and its due tomorrow night (4/16/2010). P=7t^2+8000. 8000 represents the population (p0), t is the time meaning years. t=o (2010), t=1 (2011), t=2 (2012), t=3 (2013), and t=6 (2016). This part is already figured out but the next part is not. It says:use your equation from the first part to approximate how many years it will take for the population to reach 12,000. Round to the nearset whole year when necessary. 1st answer then 2nd show the work. Can someone help me, please and thank you.

Answer by Edwin McCravy(20060) About Me  (Show Source):
You can put this solution on YOUR website!
): I have an quadratic equation that has to do with graphing and its due tomorrow night (4/16/2010). P=7t^2+8000. 8000 represents the population (p0), t is the time meaning years. t=o (2010), t=1 (2011), t=2 (2012), t=3 (2013), and t=6 (2016). This part is already figured out but the next part is not. It says:use your equation from the first part to approximate how many years it will take for the population to reach 12,000. Round to the nearest whole year when necessary. 1st answer then 2nd show the work. Can someone help me, please and thank you.

P=7t%5E2%2B8000

Substitute 12000 for P and solve for t:

12000=7t%5E2%2B8000

Subtract 8000 from both sides:

4000=7t%5E2

Divide both sides by 7

4000%2F7=t%5E2

Take square roots of both sides:

sqrt%284000%2F7%29=sqrt%28t%5E2%29

23.90457219=t

So in 23 years it will be a little less than 12000 and in 24 
years it will a little more than 12000.

To check, substitute t=23 and t=24 into

P=7t%5E2%2B8000

Substituting t=23

P=7%2823%29%5E2%2B8000

P=110703

Substituting t=24

P=7%2824%29%5E2%2B8000

P=12032

t=24 gives closest to 12000. so the answer is 24 years, or
the year 2034.

Edwin