5 books cost 20 work out the cost of 9 books​

9 books cost 32

Step-by-step explanation:

5 books =20

1 book= 5÷20 = 4

9 books = 4×9 = 32

36

Step-by-step explanation:

5books=20

9books=??

9×20=180

180÷5=36

d

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.