Find the intervals on which the function f(x) = ax2 + bx + c (where "a" doesn't = 0) is increasing and decreasing. Describe the reasoning behind your answer.

Step-by-step explanation:

Given that:

The derivative of the function of x is  

Thus; f(x) is increasing when f'(x) > 0

f(x) is decreasing when f'(x) < 0

i.e

f'(x) > 0 , when  b > 0  and a < 0

∴

2ax + b < 0

2ax < - b

f'(x) < 0 , when  b < 0  and a > 0

2ax + b > 0

2ax > - b

146%

step-by-step explanation:

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.