How can you tell whether a solution of a polynomial equation is a repeated solution when the equation is written in factored form

Example:-

(x + 1)^2(x - 1)

will have  a root -1 duplicity  2  because the (x + 1) is squared

(x - 1)^3 (x + 9)^2

-  will have 5 roots:- 1  with duplicity 3 and -9 with duplicity 2

1. 5/82.95% is better than 7/8