9 x 9 = 81
5 x (5 + 9) x 9 = 5 x 14 x 9 = 630
Just X to the second power minus nine. You can't subtract nine from x to the second power unless you know what x is.
The product of 99 x 99 is 9,801. 99 x 100=9900.
(x+3)(x-3)
if x= 3 or -3
450.
So, by that you mean x/-9? If so, you just divide x by nine and make it negative.
The Roman numeral for nine is IX. X is 10 and I is 1. When the I is before the X you subtract.
nine
89 + x = x +89
It is 9.