Question

The sum of the three consecutive number is A.P is 21 and their product is 231 .Find the numbers

Answer 1

Substitute in place of a,a+d,a+2d

Answer 2

let the three consecutive numbers be a-d,a and a+d
a-d+a+a+d=21
3a=21
a=7

(a-d)(a)(a+d)=231
(7-d)(7)(7+d)=231
         49-d^2=231/7            (a-b)(a+b)=a^2-b^2
          49-d^2=33
           49-33=d^2
                16=d^2
                  4=d
therefore the three consecutive numbers are 3, 7 and 11.