I need help with this please

a=40 degree( vertically opposite angle)

a+b+90=180( area of triangle)

or, 40+ b+ 90=180

or,b=180-130

b=50 degree

c+65=180 (st.line)

or, c= 180-65

c= 115 degree

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.