I'm struggling with factoring these two questions.

Question

36x^4 - 3x^3 - 18x^2
9x^2 + 3xy - 2y^2

Answer 1

36x^4 - 3x^3 - 18x^2
3x^2 (12x^2-x-6)
3x^2 (4x-3)(3x+2)

9x^2 + 3xy - 2y^2
(9x+)(x-) won't work; the 9 is too big

3*2 - 3*1 = 3, so
(3x+2)(3x-1)