The square of nine less than a number is three less than the number. what is the number ?

Let n represent the number.
.. (n -9)^2 = n -3 . . . . . the square of 9 less than the number is 3 less than the number
.. n^2 -18n +81 = n -3
.. n^2 -19n +84 = 0
.. (n -7)(n -12) = 0
.. n = 7 or 12

The number could be 7 or 12.


Check:
.. (7 -9)^2 = (-2)^2 = 4 = 7 -3 . . . . answer checks OK
.. (12 -9)^2 = 3^2 = 9 = 12 -3 . . . . answer checks OK