A certain number was multiplied by 7. 4 was taken away from the product. Finally, that difference was then divided by 9, resulting in 5. Find the initial number.
Pls answer asap

Answer= x = 20

Step-by-step explanation:  7 is added to it  => x+7                                                                    

sum is multiplied by 5

=> 5(x+7)

product is divided by 9

=> 5(x+7)/9

3 is subtracted from the quotient

=> 5(x+7)/9 - 3

the remainder left is 12

=> 5(x+7)/9 - 3 = 12

add 3 on both sides

=> 5(x+7)/9 = 15

multiply by 9 on both sides

=> 5(x+7) = 15 *9

=> 5(x+7) = 13

divide by 5 on both sides

=> (x+7) = 27

subtract 7 on both sides

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.