From points a and b, the distance between which is 1020 mi, two trains left simultaneously towards each other. the speed of one train was 10 mph greater than the speed of the other one. in 5 hours the trains had not met yet and were 170 mi apart. find the speed of the trains.

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.

correct answer is c. just did it

step-by-step explanation: