What is the value of x?
A.) 15
B.) 22
C.) 25
D.) 20

Step-by-step explanation:

From the same external point B, the tangents AB and BC to a circle are equal.

x+15=2x-5

=>x-2x = -5-15

=>-x = -20

=>x= 20

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.