Important: Use the symbol "^" to denote exponentiation:
x3 – 9x2 + 5x – 45 NO
x^3 – 9x^2 + 5x – 45 YES
Look at the first 2 terms. They can be rewritten as x^2(x-9). Then look at the last 2 terms. They can be rewritten as 5(x-9). So, x-9 is the common factor here. Thus, the original expression becomes:
(x^2-5)(x-9).
Note that x^2-5 can be factored, so that the final 3 factors are:
(x-sqrt(5)), (x+sqrt(5)), (x-9).