Answer:
(x - 10)(x + 9)
Step-by-step explanation:
[tex] {x}^{2} - x - 90 \\ = {x}^{2} - 10x + 9x - 90 \\ = x(x - 10) + 9(x - 10) \\ = \red{ \boxed{ \bold{ (x - 10)(x + 9) }}}\\ [/tex]
