Which step is wrong
1 pound = 100 penny
= 10 penny x 10 penny
= 1/10 pound x 1/10 pound
= 1/100 pound
= 1 penny

=> 1 pound = 1 penny

10 penny x 10 penny is incorrect = 100 penny^2

Step-by-step explanation:

We know that

1 pound = 100 penny

Factor 100 into 10 *10

               = 10 * 10 penny

10 penny * 10 penny = 100 penny^2

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.