Question 320876
Factoring completely: 
18u^5 - 6u^4 - 4u^3,
factor out 2u^3 and you have:
2u^3(9u^2 - 3u - 2)
Factor the quadratic
2u^3(3u + 1)(3u - 2)
:
Factor: Y^2 = 13y + 13,
y^2 = 13(y + 1)
:
Factor: 3Y^2 + 2y - 21,
(3y - 7)(y + 3) 
:
Factoring completely:
 27y^6 + 36y^5 + 12y^4,
Factor our 3y^4
3y^4(9y^2 + 12y + 4)
Quadratic is a perfect square
3y^4(3y + 2)(3y + 2)
:
Factor the quadratic expression:
 Y^2 + 12y + 36,
Also a perfect square
(y + 6)(y + 6)
:
Factor: 4y^2 - z^2,
The difference of squares
(2y + z)(2y - z); check this by FOILing
:
Factor completely:
 w^4y^4 -y^4,
Factor out y^4
y^4(w^4 - 1)
factor the difference of square
y^4(w^2 - 1)(w^2 + 1)
Another dif of squares, so you have:
y^4(w-1)(x+1)(w^2+1)
:
Factoring completely: 27t^3 + 125,
This is the sum of cubes, requires special factoring, look up "sum of cubes"
(3t + 5)(9t^2 - 5t + 25)
:
Factoring completely:
 t^2 - 2t + 1,
perfect square
(t - 1)(t - 1)
:
 factor: 64z^2 - 81.
Difference of squares
(8z - 9)(8z + 9)
:
:
Please don't cry now!