Answer:
(x+1)(x-1)(x+3)(x-3)
Explanation:
it is a fourth degree trinomial
1) find two number whose sum is -10 and whose product is 9
the two numbers are -1 and -9
2) write the trinomial as a multiplication in this way
(x^2-1)(x^2-9)
3) the two factors are both a difference of tho squares.
so we can rewrite it as
(x+1)(x-1)(x+3)(x-3)