Question

The sum of first three terms of an A P is 21 and their product is 231 Find the numbers

Answer 1

let the first three numbers be
a-d,a,a+d
now, ATQ
a-d + a + a+d = 21
3a = 21
a=7
ATQ
(a-d)(a)(a+d)=231
a(a^2 - d^2) = 231
7(7^2-d^2) =231
49 - d^2= 33
d^2 = 49-33
d^2 = 16
d = +/- 4
now
the numbers are
3,7,11
or
11,7,3

Answer 2

I hope it is clear to you.