A town's population is 38,800 . About 125 people move out of the town each month 175. Each month, people on average move into town. A nearby town has a population of 40,800 . It has no one moving in and an average of 150 people moving away every month. In about how many months will the populations of the towns be equal? Write an equation to model the situation. Then solve the equation and answer the question.

solution:

the given function is ,

      =

the three roots of this quadratic function is , 0 ,8 and 10.all the roots are real and rational.

if a quadratic equation is of the form ,

sum of the roots = a + b +c= 0+8+10=18=  

product of roots taken two at a time = a b + b c+ c a = 0+80+0=80 =  

product of roots = a b c = 0=  

there are 11 doors in a hall starting from 0 to 11.the entry in the hall is permitted through gate number 0 and exit is allowed through only gate number 8 and 10.so, three roots(0,8,10) of quadratic function is given by entry and exit route of this hall.

first 15 divide by 2 = 7.5

100 divided by 7.5 is 13.

15 / 2 = 7.5

100 / 7.5 = 13.