A is directly proportional to x and inversely proportional to y. If A=20 when x=6 and y=9, what is the value of A when x=9 and y=6? A) 1/20
B) 30
C) 45
D) 60

A=45

A=kx/y

where k is constant

substituting the values for k

k= 20×9/6=30

when x=9, y=6

A= 30×9/6=45

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.

step-by-step explanation: