Factoring Polynomials

1. 125x^3 - 8
2. 32x^3 - 4
3. 10x^3 + 20x^2 + x + 2
4. 2x^3 - 5x^2 + 18x - 45

Explanations if possible

(5x - 2)(25x^2 + 10x + 4) difference of two cubes

32x^3 - 4
4(8x^3 - 1)
4(2x - 1)(4x^2 + 2x + 1) common factor 4, difference of two cubes

10x^3 + 20x^2 + x + 2
10x^2(x + 2) + 1(x + 2)
(10x^2 + 1)(x + 2) factor by grouping

2x^3 + 18x - 5x^2 - 45
2x(x^2 + 9) - 5(x^2 + 9)
(2x - 5)(x^2 + 9) factor by grouping