A number is 30 less than its square .

Question

A number is 30 less than its square.find the numbers

Answer 1

A number is 30 less than its square

 

let;

x = the number

 

x = x² - 30

 

x² - x - 30 = 0

 

factor :

 

        -30

       /     \

     5       -6  =  -1

 

 

(x + 5)(x - 6) = 0

 

so the number could be either -5 or 6