Question

Which shows one way to determine the factors of x^3 - 9x^2 + 5x - 45 by grouping ?

Answer 1

You can group first two conjunctions and second two:
$x^3 - 9x^2 + 5x - 45=(x^3-9x^2)+(5x-45)$.
In first brackets you have common $x^2$ and in second brackets common is 5:
$(x^3-9x^2)+(5x-45)=x^2(x-9)+5(x-9)=(x-9)(x^2+5)$.