Could someone show me how you would do the following question.

Determine the roots algebraically by factoring:
x^3 - 8x^2 - 3x + 90= 0

after trying ±1, ±2, I found -3 to give me a zero (use only factors of 90)

so x+3 is a factor
I then used synthetic division to find the quadratic x^2 - 11x + 30 which factored into
(x-5)(x-6)

so
x^3 - 8x^2 - 3x + 90= 0
(x+3)(x-5)(x-6) = 0
and x = -3, 5, 6