Question

Find two consecutive odd integers whose product is 99

Answer 1

Let x be the first odd number.

Second odd number will be x+2

Proof:

If 3 (was) the first odd number, 3+2 would be the next which is 5.

So,

(x) (x+2) = 99
xsquare + 2x = 99
xsquare +2x - 99 = 0
xsquare +11x - 9x -99 = 0
x(x +11) -9(x + 11) = 0
(x+11) (x-9) = 0

So the two odd numbers were 9 and 11