Answer:
3
Explanation:
Let x represent the number of interest. Then x+6 is "another number". You want its square root to be the original number:
√(x+6) = x
Squaring both sides, we get ...
x +6 = x^2
In standard form, this is ...
x^2 -x -6 = 0
(x -3)(x +2) = 0 . . . . factored
By the zero product rule, this will have solutions ...
x -3 = 0 ⇒ x = 3
x +2 = 0 ⇒ x = -2 . . . . . an extraneous solution, because √(-2+6) ≠ -2
The number is 3.